Document:

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                         AMERICAN CENTER LEASE AGREEMENT

       THIS LEASE AGREEMENT (the "Lease") is made and entered into on this the
29th day of May 1997 between Met Life International Real Estate Equity Shares,
Inc., a Delaware Corporation ("Landlord") and Keyvan Rafie, a sole
proprietorship, ("Tenant").

                              W I T N E S S E T H:

       1.     Definitions.

       (a)    The "Project" shall mean the American Center Office Complex, being
the real property described in Exhibit "A" attached hereto and incorporated
herein and improvements constructed thereon.

       (b)    "Premises" shall mean the space outlined on the floor plan
attached to this Lease as Exhibit "B" incorporated herein. The Premises are
stipulated for all purposes to contain approximately 21,041 square feet of "Net
Rentable Area" (as below defined); provided, however that Landlord may, upon
completion of the Premises, cause precise measurements of the Project, the
Building (as below defined) and the Premises to be made, and Base Rental (as
below defined) shall be adjusted upward or downward accordingly. The Premises
are located in the office building (the "Building") located at 8330 Boone
Boulevard, Suite 800, Vienna, in Fairfax, Virginia.

       (c)    "Base Rental" shall mean the sum of (i) $378,738.00 per annum for
the first (1st) through the fifth (5th) year of the Lease Term (hereafter
defined) and (ii) $410,299.50 per annum for the sixth (6th) through the tenth
(10th) year of the Lease Term. [The Base Rental payable beginning on the first
(1st) day of the sixth (6th) year of the Lease Term is the sum of the Base
Rental payable during the first (lst) year of the Lease Term plus adjustments
that accrued from time to time during years one (1) through five (5) of the
Lease Term pursuant to Exhibit "D" attached hereto plus an increase of $1.50 per
square foot of Net Rentable Area contained within the Premises.] The Base Rental
due for the first (1st) month of the Lease Term (hereinafter defined) during
which Base Rental is due, has been deposited with Landlord by Tenant
contemporaneously with the execution hereof.(1)

       (d)    "Commencement Date" shall mean the later of August 14, 1992 or the
date specified in paragraph 3 (c) hereof.

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       (1) Landlord shall provide Tenant a monthly rental credit equal to
S2,630.12 for months two (2) through thirty-seven (37).

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       (e)    "Lease Term" shall mean a term commencing on the Commencement Date
and continuing until 120 calendar months after the first day of the first full
month fo1lowing the Commencement Date.

       (f)    "Security Deposit" shall mean the sum of $31,561.50. The Security
Deposit(2) deposited with Landlord by Tenant(3).

       (g)    "Common Areas" shall mean those areas devoted to lobbies,
corridors, all elevator foyers, restrooms, mechanical rooms, janitorial closets,
electrical and telephone closets, vending areas and other similar facilities
provided for the common use or benefit of tenants generally and/or the public.

       (h)    "Service Area" shall mean those areas within the outside walls of
the Building used for elevator mechanical rooms, building stairs, fire towers,
elevator shafts, flues, vents, stacks, pipe shafts, and vertical ducts (but
shall not include any such areas for the exclusive use of the particular
Tenant).

       (i)    "Net Rentable Area" of the Premises shall mean the gross area
within the inside surface of the outer glass or other material comprising the
exterior walls of the Premises, to the mid-point of any walls separating
portions of the Premises from those of adjacent tenants and to the Common Area
or Service Area side of walls separating the Premises from Common Areas and
Service Areas, subject to the following:

              (1)    Net Rentable Area shall not include any Service Areas.

              (2)    Net Rentable Area shall include a prorata part of the
Common Areas on the floor on which the Premises are located, such proration
based upon the ratio of the Net Rentable Area within the Premises to the total
Net Rentable Area on such floor, both determined without regard to the Common
Areas. The Common Area on floor(s) upon which the Premises are located shall
never exceed: 2,711 square feet and may be adjusted as determined by Landlord
from time to time to confirm such allocation to changes in the configuration or
rented spaces and Common Areas upon such floor.

              (3)    Net Rentable Area shall include any columns and/or
projection(s) which protrude into the Premises and/or the Common Areas.

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       (2) shall be

       (3) in the form of a Letter of Credit drawn against a bank reasonably
satisfactory to Landlord within fifteen (15) days of execution hereof.

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       (j)    "Exterior Common Areas" shall mean those areas of the Project
which are not located within the Building and which are provided and maintained
for the common use and benefit of Landlord and tenants of the Project generally
and the employees, invitees and licensees of Landlord and such tenants;
including without limitation all parking areas, enclosed or otherwise; all
streets, sidewalks and landscaped areas located within the Project.

       (k)    The "Improvements", when used herein, shall mean those
improvements to the Premises which Landlord has agreed to provide when approving
the plans and specifications (the "Plans") described on Exhibit "O", attached
(or to be attached) hereto and incorporated herein for all purposes. Except to
the extent otherwise agreed (and described on an addendum to the Plans), the
installation of the Improvements shall be installed by Landlord at Tenant's
expense. "Building Standard" shall mean the type, brand and/or quality of
materials Landlord designates from time to time to be the minimum quality to be
used in the Building or the exclusive type, grade or quality of material to be
used in the Building.(4)

       2.     Lease Grant. Subject to and upon the terms herein set forth,
Landlord leases to Tenant and Tenant leases from Landlord the Premises.

       3.     Lease Term.

       (a)    This Lease shall continue in force during a period beginning on
Commencement Date and continuing until the expiration of the Lease Term, unless
this Lease is sooner terminated or extended to a later date under any other term
or provision hereof.

       (b)    If by August 14, 1992 the Improvements have not been substantially
completed pursuant to the Plans (as determined by Landlord's architect in his
sole and absolute discretion), due to omission, delay or default by Tenant or
anyone acting under or for Tenant, Landlord shall have no liability because of
such delays, and the obligations of this Lease (including, without limitation,
the obligation to pay rent) shall nonetheless commence as of the Commencement
Date.

       (c)    If, however, the Improvements are not substantially completed (as
determined by Landlord's architect in his sole and absolute discretion) by
August 14, 1992, due to any reason other than an omission, delay or default by
Tenant or someone acting under or for Tenant, then, as Tenant's sole remedy for
the delay in Tenant's occupancy of the Premises, Commencement Date shall be
delayed and the rent herein provided shall not commence until the earlier to
occur of actual occupancy by Tenant of any portion of the Premises or
substantial completion of the Improvements.

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       (4) Landlord shall build out Tenant's demised premises to suit in
accordance with attached Exhibits "C" and "O". In addition, Landlord shall
provide Tenant an allowance equal to $2.00 per square foot to improve the
premises anytime between thirty six (36) and sixty (60) months of the lease
term.

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       4.     Use. The Premises shall be used for office purposes and for no
other purpose. Tenant agrees not to use or permit the use of the Premises for
any purpose and uses incidental thereto which is illegal or which, in Landlord's
opinion, creates a nuisance or which would increase the cost of insurance
coverage with respect to the Building.

       5.     Base Rental.

       (a)    Tenant agrees to pay during the Lease Term, to Landlord, without
any setoff or deduction whatsoever the Base Rental, and all such other sums of
money payable by the Tenant hereunder as additional rent (whether or not
expressly characterized as additional rent), all of which are sometimes herein
collectively called "rent", for the nonpayment of which Landlord shall be
entitled to exercise all such rights and remedies as are herein provided in the
case of the nonpayment of Base Rental. If no earlier due date is expressly
specified herein for the payment of additional rent, additional rent shall be
payable in full no later than the due date of the next following installment of
Base Rental. The annual Base Rental for each lease year or portion thereof
during the Lease Term, together with any estimated adjustments thereto pursuant
to Exhibit D hereof, shall be due and payable in advance in twelve (12) equal
installments on the first day of each calendar month during the Lease Term, and
Tenant hereby agrees to pay such Base Rental and any adjustments thereto as
additional rent to Landlord at Landlord's address provided herein (or such other
address as may be designated by Landlord in writing from time to time) monthly,
in advance, and without demand. If the term of this Lease commences on a day
other than the first day of a month or terminates on a day other than the last
day of a month, then the installments of Base Rental and any adjustments thereto
for such month or months shall be prorated, based on the number of days in such
month.

       (b)    In the event any installment of rent is not paid(5) of when due
and payable, Tenant shall pay a late charge of four percent (4%) of the
delinquent amount.

       6.     Services to be Furnished by Landlord. Landlord agrees to furnish
Tenant the following services:

       (a)    Hot and cold water at those points of supply provided for general
use of other tenants in the Building and pantry included within premises,
central heat and air conditioning in season, at such temperatures and in such
amounts as are considered by Landlord to be standard or as required by
governmental authority; provided, however, heating and air conditioning service
at times other than for "Normal Business Hours" for the Building (which are 7:30
a.m. to 6:00 p.m. on Mondays through Fridays and 8:00 a.m. to 1:00 p.m. on
Saturdays, exclusive of "Normal Business Holidays", as hereinafter defined),
shall be furnished only upon the written request of Tenant delivered to Landlord
prior to 3:00 p.m. at least 1 business day in advance of the date such usage is
requested. As used herein, Normal Business Holidays shall include all hours
after 1:00 p.m. on Saturdays, all day on Sundays and all days

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          (5) within five (5) days

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observed by the Commonwealth of Virginia or the Federal Government as legal
holidays and such other days designated as legal holidays by the applicable
building service union employee's service contract and/or by the applicable
operating engineer's contract. Tenant shall bear the entire cost of additional
service allocable to the Premises as such costs are determined and allocated by
Landlord from time to time.

       (b)    Routine maintenance and electrical lighting service for all
Exterior Common Areas(6) and Service Areas in the manner and to the extent
deemed by Landlord to be standard.

       (c)    Janitor service, Mondays through Fridays, exclusive of normal
business holidays; provided, however, if Tenant's floor covering or other
improvements require special treatment, Tenant shall pay the additional cleaning
cost attributable thereto as additional rent upon presentation of a statement
therefor by Landlord. Tenant shall cooperate with Landlord's employees in the
furnishing by Landlord of janitorial services at such times (including Normal
Business Hours) as Landlord elects to have the necessary work performed;
provided, however, that janitorial services performed by Landlord during Normal
Business Hours shall be performed in such a manner as to not unreasonably
interfere with Tenant's use of the Premises.

       (d)    Subject to the provisions of Paragraph 12, facilities to provide
all electrical current required by Tenant in its use and occupancy of the
Premise.

       (e)    All Building Standard fluorescent bulb replacement in the Premises
and fluorescent and incandescent bulb replacement in the Common Areas and
Service Areas.

       (f)    Landlord may elect to provide security in the form of limited
access to the Building during other than Normal Business Hours. In such event
Landlord may require those tenants requesting access to the Building during
other than Normal Business Hours, to pay a fee for such access partially to
reimburse Landlord for the cost of the system which limits after-hours access.
Landlord, however, shall have no liability to Tenant, its employees, agents,
invitees or licensees for losses due to theft or burglary, or for damages
done by unauthorized persons on the Premises and neither shall Landlord be
required to insure against any such losses. Tenant shall cooperate fully in
Landlord's efforts to maintain security in the Building and shall follow all
rules and regulations promulgated by Landlord with respect thereto.

       The failure by Landlord to any extent to furnish or the interruption or
termination of these defined services in whole or in part, resulting from causes
beyond the reasonable control of Landlord shall not render Landlord liable in
any respect nor be construed as an eviction of Tenant, nor work an abatement of
rent, nor relieve Tenant from the obligation to fulfill any covenant or
agreement hereof. Should any of the equipment or machinery used in the provision
of such services for any cause cease to function properly, tenant shall have no
claim for offset or abatement of rent or damages on account of an interruption
in service occasioned thereby or

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       (6) Common Areas

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resulting therefrom.

       7.     Improvements to be Made by Landlord. Except for the Improvements,
all installations and improvements now or hereafter placed on the Premises shall
be for Tenant's account and at Tenant's cost (and Tenant shall pay ad valorem
taxes and increased insurance thereon or attributable thereto), which cost shall
be payable by Tenant to Landlord in advance as additional rent.

       8.     Maintenance and Repair of Premises by Landlord. Except as
otherwise expressly provided herein, Landlord shall not be required to make any
repairs to the Premises.(7)

       9.     Graphics. Tenant shall not erect or install any sign or other type
display whatsoever, either upon the exterior of the Building, upon or in any
window or in any lobby, without the prior express written consent of Landlord.
The color and fabric of the lining of all drapes (or if unlined, the draperies
themselves) which Tenant desires to place on exterior windows or openings of the
Building must be approved by Landlord prior to the installation thereof so that
a uniform color and appearance may be preserved from the exterior of the
Building. Landlord agrees to furnish a directory of the names and locations of
its tenants and to install and maintain the same at a convenient location in the
lobby of the Building. The initial listing of the name and room number of Tenant
shall be furnished without charge. The listings of additional names or room
numbers and changes or revisions of listings shall be made by Landlord at the
cost of Tenant.

       10.    Care of the Premises by Tenant. Tenant agrees not to commit or
allow any waste to be committed on any portion of the Premises and at the
termination of this Lease to deliver up the Premises to Landlord in as good
condition as at the date of the commencement of the term of this Lease, ordinary
wear and tear and insured casualty losses excepted.

       11.    Repairs and Alterations by Tenant. Tenant covenants and agrees
with Landlord, at Tenant's own cost and expense, to repair or replace any damage
done to the Building, or any part thereof, caused by Tenant or Tenant's agents
and employees, and such repairs shall restore the Building to as good as
condition as it was in prior to such damage, and shall be effected in compliance
with all applicable laws; provided, however, if Tenant fails to make such
repairs or replacements promptly, Landlord may, at its option, make repairs or
replacements, and Tenant shall pay the cost thereof to the Landlord on demand as
additional rent. Tenant agrees with Landlord not to make or allow to be made any
alterations to the Premises, install any vending machines on the Premises, or
place signs on the Premises which are visible from outside the Premises, without
first obtaining the express written consent of Landlord in each such instance,
which consent may be given on such conditions as Landlord may elect. Any and all
alterations to the Premise shall become the property of Landlord upon
Termination of this Lease (except

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       (7) Notwithstanding the foregoing Landlord shall maintain the building
and building systems in a manner consistent with a First Class building in
Fairfax County, Virginia.

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for moveable equipment or furniture owned by Tenant). Landlord may, nonetheless,
require Tenant to remove any and all fixtures, equipment and other improvements
installed on the Premises upon expiration or prior termination of the Lease
Term. In the event that Landlord so elects, and Tenant fails to remove such
improvements, Landlord may remove such improvements at Tenant's cost, and Tenant
shall pay Landlord on demand the cost of restoring the Premises to Building
Standard.

       12.    Use of Electrical Services by Tenant. Tenant's use of electrical
services furnished by Landlord shall be subject to the following:

       (a)    Tenant's electrical equipment shall be restricted to that
equipment which individually does not have a rated capacity greater than .5
kilowatts per hour and/or require voltage other than 120/208 volts, single
phase. Collectively, Tenant's equipment shall not have an electrical design load
greater than an average of 2 watts per square foot.

       (b)    Tenant's lighting shall not have a design load greater than an
average of 2 watts per square foot.

       (c)    Landlord shall be entitled to enter the Premises to perform an
audit or survey of electrical use thereon from time to time. Tenant's
consumption of electrical services shall not exceed either the rated capacities
and/or design loads set forth in Paragraphs 12(a) and 12(b) above nor shall it
generate heat in excess of that which Landlord's air conditioning system is
designed to handle. In the event that Tenant elects to add equipment and/or
lighting to the Premises that will cause Tenant's consumption of electrical
services to exceed either the rated capacities and/or design loads set forth in
Paragraphs 12(a) and 12(b) above or that will generate heat in excess of that
which Landlord's air conditioning system is designed to handle, Tenant shall
obtain Landlord's prior written approval of such equipment and/or lighting
subject to the following:

              (i)    Tenant shall pay for all costs of installation and
       maintenance of submeters, wiring, additional air conditioning systems and
       other items required by Landlord, in Landlord's discretion, to
       accommodate Tenant's excess design loads and capacities or heat
       production.

              (ii)   Tenant shall pay to Landlord, upon demand, the cost of the
       excess demand and consumption of electrical service at rates determined
       by Landlord (which rates shall be in accordance with any applicable laws)
       as well as all costs of operating additional air conditioning systems
       deemed necessary by Landlord on account of Tenant's excess consumption.

              (iii)  Landlord may, at its option, upon not less than thirty (30)
       days' prior written notice to Tenant, discontinue the availability of any
       or all utility service and in such event Tenant shall contract directly
       with such public utility for the supplying of such additional utility
       service to the Premises.

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       13.    Parking. During the Lease Term, Tenant shall have the
non-exclusive use in common with Landlord, other tenants of the Building, their
guests and invitees, of the non-reserved common automobile parking areas,
driveways, and footways, subject to rules and regulations for the use thereof as
prescribed from time to time by Landlord. Landlord reserves the right to
designate parking areas within the Project or in reasonable proximity thereto,
for Tenant and Tenant's agents and employees. Cars not parked according to the
rules and regulations promulgated by Landlord may be towed at the owner's
expense. Tenant shall provide Landlord with a list of all license numbers for
the cars owned by Tenant, its agents and employees from time to time upon
demand. In the event that Tenant, its agents and employees, park in locations
other than those assigned to Tenant, Landlord reserves the right to charge
Tenant as additional rental hereunder Twenty-Five Dollars ($25) per diem for
each such occurrence in addition to towing such cars at Tenant's expense.
Landlord will designate special parking areas located within the Project for
reserved parking for tenants of the Project who will rent such parking spaces.
In the event Tenant leases any such rental parking spaces from Landlord, the
terms and conditions of such lease shall be as set forth in that certain Parking
Space Rental Agreement attached hereto as Exhibit "F" and incorporated herein by
reference.

       14.    Laws and Regulations. Tenant agrees at Tenant's expense to comply
with all applicable laws, ordinances, rules, and regulations of any governmental
entity or agency having jurisdiction of the Premises.

       15.    Building Rules. Tenant will comply with the rules of the Building
and Project reasonably adopted and altered by Landlord from time to time and
will cause all of its agents, employees, invitees and visitors to do so; all
changes to such rules will be sent by Landlord to Tenant in writing. The initial
rules for the Building and the Project being attached hereto as Exhibit "E" and
incorporated herein for all purposes.

       16.    Entry by Landlord. Tenant agrees to permit Landlord or its agents
or representatives to enter into and upon any part of the Premises at all
reasonable hours (and in emergencies at all times) to inspect the same, or to
show the Premises to prospective purchasers, mortgagees, tenants, or insurers,
to clean or make repairs, alterations or additions thereto, and Tenant shall not
be entitled to any abatement or reduction of rent by reason thereof. Tenant
agrees to cooperate with Landlord in event of emergencies, including, without
limitation, evacuation at Landlord's oral request in the event of any situation
deemed by Landlord as an emergency.

       17.    Assignment and Subletting. Tenants shall not assign, sublease or
transfer any or all of the Premises without the prior written consent of
Landlord, such consent shall not be unreasonably withheld. In the event of any
such assignment or subletting consented to by Landlord. Tenant shall remain
fully and primarily liable for the payment of rent due under this Lease and for
the performance of all the covenants, agreements, terms, conditions and
provisions under this Lease. Additionally, Tenant's assignee or sublessee shall
be required to assume all of Tenant's obligations under this Lease. The Landlord
hereby grants to Tenant the right to sublease up to fifty percent (50%) of the
Premises without the Landlord participating in any of

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the profit derived from said subleasing. In the event that Tenant desires to
sublease more than fifty percent (50%) of the Premises, Tenant shall give
Landlord thirty (30) days written notice of Tenant's intention to do so. Within
thirty (30) days of receipt of said notice, Landlord shall have the right to:

       (a)    Take possession of or;

       (b)    Participate in fifty percent (50%) of profits derived from said
              subleasing or;

       (c)    Notify Tenant, in writing, of Landlord's consent to allow Tenant
              to sublease said space.

       18.    Mechanic's Liens. Tenant will not suffer or permit any mechanic's
lien or liens to be placed upon the Premises or the Building arising out of any
work contracted for or authorized by Tenant in respect to the Premises and
nothing in this Lease shall be deemed or construed in any way as constituting
the consent or request of Landlord, express or implied, by inference or
otherwise, to any person for the performance of any labor or the furnishing of
any materials to the Premise, or any part thereof, nor as giving Tenant any
right, power, or authority to contract for or permit the rendering of any
services or the furnishing of any materials that would give rise to any
mechanics' or other liens against the Premises. In the event any such lien is
attached to the Premises or Tenant's interest therein Tenant shall immediately
cause same to be released, and if Tenant fails to do so, then, in addition to
any other right to remedy of Landlord, Landlord may, but shall not be obligated
to, discharge the same. Any amount paid by Landlord for any of the aforesaid
purposes and costs incurred by Landlord with respect thereto, shall be paid by
Tenant to Landlord on demand as additional rent.

       19.    Insurance.

       (a)    Landlord shall maintain fire and extended coverage insurance on
the Building and the Premises in such amounts as Landlord or its mortgages shall
require, payable solely to Landlord or the mortgagees of Landlord as their
interests shall appear. Tenant shall maintain, at its expense, fire and extended
coverage insurance on all of its personal property, including removable trade
fixtures, equipment, installations and contents located in the Premise and in
such additional amounts as are necessary to meet Tenants' obligations pursuant
to paragraph 23 hereof. Tenant shall, at Landlord's request from time to time,
provide Landlord with current certificates of insurance evidencing Tenant's
compliance with this Paragraph 19(a) and Paragraph 19(b). Tenant shall obtain
the agreement of Tenant's insurers to notify Landlord that a policy is due to
expire at least 10 days prior to such expiration.

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       */ the proposed sublease portion of the premise

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       26.    Events of Default/Remedies.

              (a)    The following events shall be deemed to be events of
default by Tenant under this Lease (i)(16) or Tenant shall fail to comply with
any provision of this Lease or any other agreement between Landlord and Tenant,
all of which terms, provisions and covenants shall be deemed material (17) (ii)
the leasehold hereunder demise shall be taken on execution or other process of
law in any action against Tenant or Tenant shall become insolvent or unable to
pay its debts as they become due, or Tenant notifies Landlord that it
anticipates either condition; (iii) Tenant shall fail to move into and take
possession of the Premises(18) when the Premises are ready for occupancy, it
shall at any time vacate the Premises without Landlord's prior written approval;
(iv) Tenant takes any action to, or notifies Landlord that Tenant intends to
file a petition under any section or chapter of the National Bankruptcy Code, as
amended, or under any similar existing or subsequently enacted law or statute of
the United States or any State thereof, or a petition shall be filed against
Tenant under any such statute or (v) a receiver or trustee shall be appointed
for Tenant's leasehold interest in the Premises or for all or a substantial part
of the assets of Tenant.

              (b)    Upon the occurrence of any event or events of default by
Tenant, whether enumerated in this Paragraph or not, Landlord shall have the
option to pursue any one or more of the following remedies without any notice or
demand for possession whatsoever (and without limiting the generality of the
foregoing, Tenant hereby specially waives notice and demand for payment of rent
or other obligations due and waives any and all other notices or demand
requirements imposed by applicable law): (i) terminate this Lease in which event
Tenant shall immediately surrender the Premises to Landlord; (ii) terminate
Tenant's right to occupy the Premises and re-enter and take possession of the
Premises (without terminating this Lease); (iii) enter upon the Premises and do
whatever Tenant is obligated to do under the terms of this Lease; and Tenant
further agrees that Landlord shall not be liable for any damages resulting to
the Tenant from such action; and (iv) exercise all other remedies available to
Landlord at law or in equity, including, without limitation, injunctive relief
of all varieties.

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  (16) Tenant shall fail to comply with any provision of this Lease (or any
other agreement between Landlord and Tenant) requiring the payment of money and
such failure shall continue for a period of ten (10) days following written
notice thereof from Landlord to Tenant of such default;

  (17) and such failure shall continue for more than thirty (30) days following
notice thereof from Landlord to Tenant;

  (18) within twenty (20) days of

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              In the event Landlord elects to re-enter or take possession of the
Premises after Tenant's defau1t(19). Tenant hereby waives notice of such reentry
or repossession and of Landlord's intent to re-enter or take possession.
Landlord may, without prejudice to any other remedy which it may have for
possession or arrearage in rent, expel or remove Tenant and any other person who
may be occupying said Premises or any part thereof. Whether or not Landlord
elects to terminate this Lease in connection with a default by Tenant, Landlord
shall be entitled to reimbursement of all cost and expenses (including, without
limitation, tenant finish costs and commissions) incurred in respect of a
reletting all or a portion of the Premises occasioned by Tenant's default. In
addition, interest shall accrue on sums due hereunder from Tenant but not paid,
at the lesser of 18% per annum or the highest rate permitted by applicable law.
The provisions of Paragraph 28 hereof shall apply with respect to the period
from and after written notice to Tenant of termination. All of Landlord's
remedies shall be cumulative and not exclusive. Forbearance by Landlord to
enforce one or more of the remedies herein provided upon an event of default
shall not be deemed or construed to constitute a waiver of such default.

              (c)    This Paragraph 26 shall be enforceable to the maximum
extent not prohibited by applicable law, and the unenforceability of any portion
thereof shall not thereby render unenforceable any other portion. To the extent
any provision of applicable law request some action by Landlord to evidence or
effect the termination of this Lease or to evidence the termination of Tenant's
right of occupancy, Tenant and Landlord hereby agree that written notice, to
Tenant, or which comes to the attention of Tenant, which expressly reflects
Landlord's intention to terminate, shall be sufficient to evidence and effect
their termination herein provided for.

              (d)  **In no event shall Tenant have the right to terminate or
rescind this Lease as a result of Landlord's default of any covenant or
agreement contained in this Lease or as a result of the breach of any promise or
inducement hereof, whether in this Lease or elsewhere. Tenant hereby waives such
remedied of termination and rescission and hereby agrees that Tenant remedies
for default hereunder and for breach of any promise or inducement shall be
limited to a suit for damages and/or injunction. In addition, ** Tenant hereby
covenants that, prior to the exercise of any such remedies, it will give the
mortgages on the Building notice and a reasonable time to cure any default by
Landlord(20)

       27.    Peaceful Enjoyment. Tenant shall, and may peacefully have, hold,
and enjoy the Premises, subject to the other terms hereof, provided that Tenant
pays the rent and other sums herein recited to be paid by Tenant and performs
all of Tenant's covenants and agreements herein contained. This covenant and any
and all other covenants of Landlord shall be binding

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  (19) provided the aforementioned notice of default has been given to Tenant as
specified in Paragraphs 26(a) and 26(b)

  (20) provided Tenant has been given written notice of such mortgages and an
address where notices should be sent.

                                       14
<PAGE>   12

upon Landlord and its successors only with respect to breaches occurring during
its or their respective periods of ownership of the Landlord's interest
hereunder.(21)

       28.    Holding Over. In the event of holding over by Tenant without
Landlord's written consent after the expiration or other termination of this
Lease or in the event Tenant continues to occupy the Premises after the
termination of Tenant's right of possession pursuant to Paragraph 26(b) (ii)
hereof, Tenant shall, throughout the entire holdover period, pay rent equal on a
per diem basis, to twice the Base Rental and additional Base Rental, as adjusted
or increased under Exhibit "D" hereto, which would have been applicable had the
term of this Lease continued through the period of such holding over by Tenant.
No holding over by Tenant after the expiration of the term of this Lease shall
be construed to extend the term of this Lease.

       29.    Subordination to Mortgage. Tenant agrees that this Lease is and
shall be junior and subordinate to any first mortgage, added of trust or other
lien presently existing or hereafter arising upon the Premises, upon the
Building or upon the Project as a whole or any part thereof, and to any
renewals, modifications, consolidations, replacements, refinancing, and
extensions thereof, but Tenant agrees that any such first mortgagee shall have
the right at any time to subordinate such mortgage, added of trust or other lien
to this Lease on such terms and subject to such conditions as such mortgagee may
deem appropriate in its discretion. Landlord is hereby irrevocably vested with
full power and authority to subordinate this Lease to any mortgage, deed of
trust or other lien now existing or hereafter placed upon the Premises, the
Building or the Project as a whole or any part hereof, and to any renewals,
modifications, consolidations, replacements, refinancing and extensions thereof,
and Tenant agrees within fifteen (15) days to execute such further instruments
subordinating this Lease or attorning to the holder of any such liens as
Landlord may request. In the event that Tenant should fail to execute any
instrument of subordination herein required to be executed by Tenant within
fifteen (15) days of Landlord's demand, Tenant hereby irrevocably constitutes
Landlord as its attorney-in-fact to execute such instrument in Tenant's name,
place and stead, it being agreed that such power is one coupled with an
interest. Tenant agrees that it will from time to time upon request by Landlord
execute and deliver to such persons as Landlord shall request a statement in
recordable form certifying that this Lease is unmodified and in full force and
effect (or if there have been modifications, that the same is in full force and
effect as so modified), stating the dates to which rent and other charges
payable under this Lease have been paid, stating that Landlord is not in default
hereunder (or if Tenant alleges a default stating the nature of such alleged
default) and further stating such other matters as Landlord shall reasonably
require.

       30.    Landlord's Lien. Tenant hereby grants to Landlord a lien and
security interest on all property of Tenant now or hereafter placed in or upon
the Premises, and such property shall be and remain subject to such lien and
security interest of Landlord for payment of all rent

----------

   (21) Landlord warrants, that as of the date of this Lease, Landlord
possesses the unencumbered fee simple title to the project.

                                       15
<PAGE>   13

and other sums agreed to be paid by Tenant herein.(22) The Provisions of this
paragraph relating to such lien and security interest shall constitute a
security agreement under and subject to Virginia Uniform Commercial Code so that
Landlord shall have and may enforce a security interest on all property of
Tenant now or hereafter placed in or on the Premises, in addition to and
cumulative of the Landlord's liens and rights provided by law or by the other
terms and provisions of this Lease. Tenant agrees to execute as debtors such
financing statement or statements as Landlord may now or hereafter request.
Landlord may at its election at any time file a copy of this Lease as a
financing statement. Notwithstanding the above, Landlord shall neither sell nor
withhold from Tenant, Tenant's business records.

       31.    Attorney's Fees. In the event either party defaults in the
performance of any of the terms of this Lease and the other party employs an
attorney in connection therewith, the defaulting party agrees to pay the
prevailing party's reasonable attorney's fees. In the event that Landlord
remedies a default by Tenant pursuant to Paragraph 26(b) (iii), Landlord shall
be entitled to reimbursement by Tenant on demand for all costs incurred in
connection with same (including without limitation attorney's fees), plus
interest thereon at the highest rate permitted by law.

       32.    No Implied Waiver. No provision of this Lease shall be deemed to
have been waived by Landlord unless such a waiver be in writing signed by
Landlord. The failure of Landlord to insist at any time upon the strict
performance of any covenant or agreement or to exercise any option, right, power
or remedy contained in this Lease shall not be construed as a waiver or a
relinquishment thereof for the future. No payment by Tenant or receipt by
Landlord of a lesser amount than the monthly installment of rent due under this
Lease shall be deemed to be other than on account of the earliest rent due
hereunder, nor shall any endorsement or statement on any check or any letter
accompanying any check or payment of rent be deemed an accord and satisfaction,
and Landlord may accept such check or payment without prejudice to Landlord's
right to recover the balance of such rent or pursue any other remedy in this
Lease provided. No agreement to accept a surrender of this Lease shall be valid
unless in a writing signed by Landlord. The receipt by Landlord of rent with
knowledge of the breach of any covenant of this Lease shall not be deemed a
waiver of such breach.

       33.    Personal Liability. The liability of Landlord to Tenant for any
default by Landlord under the terms of this Lease shall be limited to the
interest of Landlord in the Building and the land described on Exhibit "A"
attached hereto is situated and Tenant agrees to look solely to Landlord's
interest in the Building and the land on which the Building is situated for the
recovery of any judgement from the Landlord, it being intended that neither
Landlord nor any partner or principal of Landlord nor any other property
disclosed or undisclosed of such partners or principals shall be personally
liable for any judgement or deficiency.

----------

  (22) provided however, said lien shall be subordinate to the original security
interest if any, previously granted in the purchase of the property.

                                       16
<PAGE>   14

       34. Security Deposit. The Security Deposit shall be held by Landlord
without liability for interest and as security for the performance by Tenant of
Tenant's covenants and obligations under this Lease, it being expressly
understood that the Security Deposit shall not be considered as advance payment
of rental or a measure of Tenant's damages in case of default by Tenant. Unless
otherwise provided by mandatory non-waivable law or regulation, Landlord may
commingle the Security Deposit with Landlord's other funds. Landlord may, from
time to time, without prejudice to any other remedy, use the Security Deposit to
the extent necessary to make good any arrearages of rent or to satisfy any other
covenant or obligation of Tenant hereunder. Following any such application of
the Security Deposit, Tenant shall pay to Landlord on demand the amount so
applied in order to restore the Security Deposit to its original amount. If
Tenant is not in default at the termination of this Lease, the balance of the
Security Deposit remaining after any such application shall be returned by
Landlord to Tenant. If Landlord transfers its interest in the Premises during
the term of this Lease, Landlord must assign the Security Deposit to the
transferee and thereafter shall have no further reliability for the return of
such Security Deposit.

       35. Notice. Any notice in this Lease provided for must, unless otherwise
expressly provided herein, be in writing, and shall, unless otherwise in this
Lease expressly provided, be given or be served by depositing the same in the
United States mail, postpaid and certified, with return receipt required,
addressed to the party to be notified at the address stated in this Lease or
such other address notice of which has been given to the other party. Any notice
shall be effective upon its deposit in the United States mail in the manner
hereinabove described. Any responses by Tenant to Landlord upon any such notice
shall be given not later than five (5) business days following the date set
forth as the date of receipt on the return receipt. Copies of any Notice to
Landlord, shall also be served upon (i) Vice President, Real Estate Investments,
Northeastern office, Metropolitan Life Insurance Company, One Madison Avenue,
New York, New York, 10010 and (ii) Manager, Real Estate Investments, Suite 410,
1615 L Street, N.W., Washington D.C. 20036.

       36. Severability. If any term of provision of this Lease, or the
application thereof to any person or circumstances shall, to any extent, be
invalid or unenforceable, the remainder of this Lease, or the application of
such term or provision to persons or circumstances other than those as to which
it is held invalid or unenforceable, shall not be affected thereby, and each
term and provision of this Lease shall be valid and enforceable to the fullest
extent permitted by law.

       37. Recordation. Tenant agrees not to record this Lease or any memorandum
or copy thereof.

       38. Governing Law. This Lease and the rights and obligations of the
parties hereto shall be interpreted, construed, and enforced in accordance with
the laws of the Commonwealth of Virginia.

                                       17
<PAGE>   15

       39. Force Majeure. Whenever a period of time is herein prescribed for the
taking of any action by Landlord, Landlord shall not be liable or responsible
for, and there shall be excluded from the computation of such period of time,
any delays due to strikes, riots, acts of God, shortages of labor or materials,
war, governmental laws, regulations or restrictions, or any other cause
whatsoever beyond the control of Landlord.

       40. Time of Performance. Except as expressly otherwise herein provided,
with respect to all required acts of Landlord and Tenant, time is of the
essence of this Lease.

       41. Transfers by Landlord. Landlord shall have the right to transfer and
assign, in whole or in part, all its rights and obligations hereunder and in the
Building, Project and property referred to herein, and in such event and upon
such transfer Landlord shall be released from any further obligations hereunder,
and it shall be deemed and construed as a covenant running with the land without
further agreement between the parties or their successors in interest, or
between the parties and the transferee of the Building, or of the land described
in Exhibit "A" and the Building that the transferee has assumed and agreed to
carry out any and all covenants and obligations of Landlord hereunder. Tenant
agrees to look solely to such successor in interest of Landlord for the
performance of such obligations.

       42. Commissions. Tenant hereby indemnifies and holds Landlord harmless
against any loss, claim, expense or liability with respect to any commissions
brokerage fees claimed on account of the execution and/or renewal of this Lease
due to any action of Tenant.

       43. Effect of Delivery of This Lease. Landlord has delivered a copy of
this Lease to Tenant for Tenant's review only, and the delivery hereof does not
constitute an offer to Tenant or option. This Lease shall not be effective until
a copy executed by both Landlord and Tenant is delivered to and accepted by
Landlord.

       44. Exhibits. Exhibits, "A", "B", "C", "D", "E", "F", "G", "H", "I",
"J", "L", "M", "N" and "O" are attached hereto and incorporated herein and made
a part of this Lease for all purposes.

       The parties acknowledge that the Tenant's name, Keyvan Rafei, has been
       misspelled as Keyvan Rafie in various references in this document, and
       agree that all such misspellings refer to the Tenant, Keyvan Rafei.

                                       18

<PAGE>   16

        IN WITNESS WHEREOF, Landlord and Tenant have executed this Lease in
multiple original counterparts as of the day and year first above written.

ADDRESS:                           LANDLORD: Met Life International
                                   Real Estate Equity Share Inc., a
8300 Boone Boulevard               Delaware Corporation
Suite 200
Vienna, VA 22182

                                   By:   /s/  MICHAEL J. CURRAN      GG
                                      ---------------------------------
                                            Michael J. Curran
                                   Title:   Assistant Vice President
                                          -----------------------------
                                   Date:          5/29/92
                                          -----------------------------

ADDRESS:                           TENANT: Keyvan Rafie, a sole proprietorship

                                   By:   /s/ KEYVAN RAFIE
                                      ---------------------------------
                                            Keyvan Rafie
                                   Title:   A Sole Proprietorship
                                          -----------------------------
                                   Date:            5-18-92
                                          -----------------------------

ATTEST:

     [SIG]
-------------------

Affix Seal:

                                       19

<PAGE>   17

                              AMERICAN CENTER LEASE
                                LIST OF EXHIBITS

This List of Exhibits is attached hereto and made a part of the Lease dated
May 29, 1992, by and between AMERICAN CENTER ("Landlord") and Keyvan Rafie,
a sole proprietorship, ("Tenant").

<TABLE>
<S>                   <C>                              <C>    <C>
                       EXHIBIT "A"                      -        Description

                       EXHIBIT "B"                      -        Outline Demised Premises

                       EXHIBIT "C"                      -        Tenant Improvements (Workletter)

                       EXHIBIT "D"                      -        Rental Escalation

                       EXHIBIT "E"                      .        Rules & Regulations

                       EXHIBIT "F"                      -        Parking Space Rental Agreement

                       EXHIBIT "G"                      -.       Termination Option

                       EXHIBIT "H"                      -        Expansion Option

                       EXHIBIT "I"                      -        Renewal Option

                       EXHIBIT "J"                      -        Indemnity Agreement

                       EXHIBIT "L"                      -        First Right of Refusal

                       EXHIBIT "M"                      -        Furniture Inventory

                       EXHIBIT "N"                      -        Signage

                       EXHIBIT "O"                      -        Tenants Plans
</TABLE>

<TABLE>
<S>                                                     <C>
 TENANT:  Keyvan Rafie, a sole proprietorship           LANDLORD: Met Life International Real
                                                        Estate Equity Shares, Inc., a Delaware
                                                        corporation

By:  /s/ KEYVAN RAFIE                                   By:   /s/  MICHAEL J. CURRAN      GG
   -------------------                                     ---------------------------------
      Keyvan Rafie                                                   Michael J. Curran

Title: A Sole Proprietorship                            Title:   Assistant Vice President
       ---------------------                                   -----------------------------
Date:       5-18-92                                     Date:          5/29/92
      ----------------------                                   -----------------------------

</TABLE>

<PAGE>   18

                                   EXHIBIT "A"

This Exhibit "A" is attached hereto and made a part of the Lease dated May 24,
1992, by and between Met Life International Real Estate Equity Shares,
Inc., ("Landlord") and Keyvan Rafie, a sole proprietorship ("Tenant").

All that certain lot, piece or parcel of land situate, lying and being in the
County of Fairfax, Virginia and being more particularly described as follows:

          Beginning at a point marking the intersection of the Southerly R/W
          line of Chain Bridge Road (Route # 123) and the Northeasterly R/W line
          of Boone Boulevard; thence with the said R/W line of Route 123 N 57
          11' 27" E, 77.04 feet with a curve to the right whose radius is 676.20
          feet (and whose chord is N 64 45' 25" E, 202.58 feet) an arc distance
          of 203.35 feet; N 73 22' 19" E, 34.26 feet; N 41 23' 12" W, 29.37 feet
          and N 73 22' 19" E, 36.02 feet to a point; thence departing Chain
          Bridge Road and running with the Southerly R/W line of a ramp for an
          interchange from said Chain Bridge to Leesburg Pike (Route #7) the
          following courses: with a curve to the right whose radius is 200.00
          feet (and whose chord is S 63 34' 18" E, 97.06 feet) an arc distance
          of 98.04 feet with a curve to the left whose radius is 302.00 feet
          (and whose chord is N 87 49' 41' E, 409.17 feet) an arc distance of
          449.54 feet; N 45 11' 05" E, 48.58 feet and with a curve to the right
          whose radius is 100.00 feet (and whose chord is N 65 04' 50' E, 68.06
          feet an arc distance of 69.45 feet to a point on the Southerly R/W
          line of Leesburg Pike (Route #7); thence with said R/W line of
          Leesburg Pike S 44 48' 55" E, 110.10 feet to a point marking the
          intersection of the said R/W line of Leesburg Pike and the
          Northwesterly R/W line of Howard Avenue; thence with the said R/W line
          of Howard Avenue S 44 49' 03" W, 552.21 feet to a point marking the PC
          of a 30 foot radius return to the intersection of Howard Avenue on the
          aforementioned Boone Boulevard; thence with said return a curve to the
          right whose chord is S 80 39' 28" W, 35.13 feet, an arc distance of
          37.53 feet to a point on the aforementioned R/W line of Boone
          Boulevard; thence with the said R/W line of Boone Boulevard N 63 30'
          09" W, 605.17 feet, to the point of the beginning containing 4.83879
          acres of land.

<TABLE>
<S>                                                                       <C>
TENANT: Keyvan Rafie, a sole proprietorship                               LANDLORD: Met Life International Real
                                                                          Estate Equity Shares, Inc., a Delaware
                                                                          corporation

By: /s/ KEYVAN RAFIE                                                      By: /s/ MICHAEL J. CURRAN         GG
   --------------------------                                                ---------------------------------
           Keyvan Rafie                                                                              Michael J. Curran
Title: A Sole Proprietorship                                              Title: Assistant Vice President
      -------------------------                                                 -------------------------------
Date: 5-18-92                                                             Date:  5/29/92
      ------------------------                                                 -------------------------------
</TABLE>

<PAGE>   19
                                  EXHIBIT "B"

                                    [GRAPH]

This Exhibit "B" is attached hereto and made a part of the Lease dated May 29
1992, by and between Met Life International Real Estate Equity Shares. Inc.,
("Landlord") and Keyvan Rafie, a sole proprietorship ("Tenant").

TENANT: Keyvan Rafie,                    LANDLORD: Met Life International Real
a sole proprietorship                    Estate Equity Shares, Inc., a Delaware
                                         corporation

By:  /s/ KEYVAN RAFIE                    By:   /s/ MICHAEL J. CURRAN
   --------------------------------         ------------------------------------
           Keyvan Rafie                           Michael J. Curran
Title:     A Sole Proprietorship         Title:   Assistant Vice President
       ----------------------------            ---------------------------------
Date: 5-18-92                            Date:  5/29/92
      -----------------------------            ---------------------------------

<PAGE>   20

                                   EXHIBIT "C"

This Exhibit "C" is attached hereto and made a part of the Lease dated May 29,
1992, by and between Met Life International Real Estate Equity Shares, Inc.,
("Landlord") and Keyvan Rafie, a sole proprietorship, ("Tenant").

Landlord, at its expense, shall prepare a plan or sets of plans (which said plan
or sets of plans, as the case may be, is hereinafter called the "Tenant
Drawings") including dimensions necessary to construct and finish the demised
premises. In accordance with the Tenant Drawings dated 4-23-92, Landlord, at
Landlord's expense, except as otherwise expressly specified in this Exhibit "C"
and in the foregoing Lease shall furnish, install in and to the demised premises
the following, all of which shall be material, manufacture, design, capacity,
finish and color of the Building Standard adopted by Landlord for the Building:

1.     PARTITIONING:

       (a)    Drywall partitions consisting of 5/8" thickness on each side taped
              and sanded to the underside of the ceiling.

       (b)    Partitions terminating at the Building exterior walls shall meet
              either a mullion or column without interfering with access to the
              peripheral enclosure.

       (c)    Demising partitions consisting of 5/8" thickness on each side
              taped and sanded to the underside of the ceiling. Walls shall be
              insulated.

2.     DOORS AND HARDWARE:

       (a)    Suite entry door will be full height solid core, 8'4" x 3'0"
              laminate wood grain veneer finish entrance door, installed in an
              anodized aluminum frame, equipped with exposed closer, with a
              l'0" sidelight.

              All doors off the common hallways shall have heavy duty lever
              handle lockset with closer.

              All interior doors will be flush, solid core, "laminate, wood
              grain veneer" full height 8'4" x 3'0" installed in an anodized
              aluminum frame with a latch-set.

3.     CEILINGS:

       (a)    Tegular acoustical tile, 2' x 2' on an exposed grid mounting
              system installed throughout.

4.     FLOOR COVERING AND BASE MOLDING:

       (a)    Tenant will be allowed up to $1.00 per square foot of leased area
              for carpeting, vinyl base and padding or Tenant may select from
              Landlord's building standard carpet selections, building standard
              carpet padding is provided by Landlord.

<PAGE>   21

5.     ELECTRICAL:

       (a)    Single pole light switches.

       (b)    120 volt duplex wall receptacle outlets.

6.     TELEPHONE:

       (a)    Building Standard wall telephone outlet with ring and pull string.

7.     WINDOW COVERING:

       (a)    Landlord shall provide Building Standard thin line horizontal
              venetian blinds on all exterior windows.

8.     PAINTING:

       (a)    Partitions and walls shall be finished with flat latex paint.
              Painting shall be in colors to be selected by Tenant from
              Landlord's Building Standard color chart, not to exceed one color
              per room.

9.     LIGHTING:

       (a)    Recessed three (3) tube 2' x 4' Parabolic Building Standard
              fluorescent light fixtures.

10.    ENTRANCE DOOR LETTERING:

       (a)    The Landlord shall provide the suite number and Tenant's name
              (excluding logos or names of individual officers and/or partners,
              other than the actual firm name) using Landlord's Building
              Standard character Building Logo.

11.    HEATING/VENTILATION AND AIR CONDITIONING:

       (a)    Landlord will provide Building Standard heating, cooling and
              circulating air equipment and controls for normal office use. The
              system shall be all electric, operated and maintained by Landlord
              at Landlord's expense.

       (b)    Any excess capacity, special controls, or exhaust required by
              Tenant shall be provided by Landlord at Tenant's expense.

       (c)    Capability for after hours air conditioning will be provided for
              by Landlord. Expense for after hours use shall be Tenant's.

<PAGE>   22

12.    SPACE PLANNING:

       (a)    Up to two (2) preliminary architectural Tenant drawings will be
              provided by the Landlord's selected architect or design firm at
              Landlord's expense.

       (b)    Any additional preliminary drawings or any sections, elevations or
              details or any specifications of non-Building Standard work shall
              be at Tenant's expense.

It is agreed that the Tenant will furnish to the Landlord all information
regarding its partitioning, electrical, mechanical and telephone requirements
and all other pertinent data by not later than June 15, 1992. Within five (5)
days after Landlord's submission of working drawings, the Tenant shall approve
of said drawings in writing. In the event Tenant fails to comply with either of
the aforesaid time requirements, any delay in completing the demised premises
shall not in any manner affect the Commencement Date as provided in the
foregoing Lease, under such circumstances Landlord agrees to make the demised
premises ready for Tenant's occupancy not later than the Commencement Date,
plus the number of days resulting from Tenant's failure to comply with the
provisions of this paragraph.

If Tenant requests any additional work which is not provided for in the
aforesaid "Building Standard Tenant Allowances", Tenant will be responsible for
all costs resulting from such additional work, including architectural and
engineering charges, which costs shall be paid by Tenant on or before occupancy
of the demised premises. Tenant understands that no credits will be given for
any portion of the allowances specified above which are not required by Tenant.

If there are any changes requested by Tenant, after completion of Tenant
Drawings, Tenant will be responsible for all architectural and engineering costs
and related expenses resulting from such changes. No such changes will be made
without written approval of the Landlord and only after written request of the
Tenant to the Landlord.

Tenant agrees to pay to Landlord, promptly upon being billed therefore, the cost
of all such work, together with ten percent (10%) overhead, and ten percent
(10%) profit on such costs. Tenant will be billed for seventy-five percent (75%)
of said costs on such non-standard or additional work at the commencement of
construction of the space and twenty-five percent (25%) when work is complete,
as determined by Landlord's architect, engineer and/or contractor.

TENANT: Keyvan Rafie, a                   LANDLORD: Met Life International Real
sole proprietorship                       Estate Equity Shares, Inc., a Delaware
                                          corporation

By: /s/ KEYVAN RAFIE                      By: /s/ MICHAEL J. CURRAN       GG
   -------------------------------           -------------------------------
       Keyvan Rafie                                            Michael J. Curran
Title: A Sole Proprietorship              Title: Assistant Vice President
      ----------------------------              ----------------------------

Date:     5-18-92                         Date:         5/29/92
     -----------------------------             -----------------------------

<PAGE>   23

                                   EXHIBIT "D"

This Exhibit "D" is attached hereto and made a part of the Lease dated May 29,
1992, by and between Met Life International Real Estate Equity Shares, Inc.,
("Landlord") and Keyvan Rafie, a sole proprietorship ("Tenant").

          1.  Basic Cost Increase Adjustment. The Base Rental payable hereunder
       shall be adjusted from time to time in accordance with the following
       provisions:

              (a) The Building contains 324,668 square feet of Net Rentable Area
       in aggregate. Tenant's Base Rental is based, in part, upon the estimate
       that annual Basic Costs will be equal to $7.75 per square foot of Net
       Rentable Area in the Building (such estimate being hereinafter referred
       to as the "Expense Stop"). Tenant shall, when Landlord so requires during
       the term of this lease, pay as an adjustment to Base Rental hereunder,
       regardless of rental abatement, an amount (per each square foot of Net
       Rentable Area within the Premises, including those portions of Common
       Areas allocated to the Premises from time to time) equal to the excess
       ("Excess") from time to time of actual Basic Costs per square foot of Net
       Rentable Area in the Building over the amount of the Expense Stop.
       Landlord may collect such additional Base Rental in arrears. Landlord
       shall also have the option to make a good faith estimate of the Excess
       for each upcoming calendar year and may require the monthly payment of
       Base Rental adjusted in accordance with such estimate. Any amounts paid
       based on such an estimate shall be subject to adjustments pursuant to
       Paragraph 1(b) of this Exhibit "D" when actual Basic Costs are available
       for each calendar year.(1)

              (b) Tenant at its' expense shall have the right no more frequently
       than once per calendar year, following prior written notice to Landlord,
       to audit through an independent certified public accountant reasonably
       acceptable to Landlord, at Tenant's sole expense, Landlord's books and
       records relating to Basic Costs during the year preceding such audit. In
       the event such an audit demonstrates additional Base Rental collected for
       such preceding year to be higher or lower than the amount of additional
       rental paid pursuant to 1(a) above, then Landlord shall refund any
       overpayment or Tenant shall pay any deficiency within ten (10) days of
       such determination.

       ---------------------

          (1) Notwithstanding the foregoing, the amount of any excess payable by
       Tenant relating to Basic Costs other than property taxes and assessments
       and utility costs shall not in any event increase by greater than six
       percent (6%) per year.

<PAGE>   24

          2.  "Basic Costs" shall mean all direct and indirect costs and
       expenses in each calendar year of operating, maintaining, repairing,
       managing and owning (including without limitation, property taxes and
       assessments) the Building and the Exterior Common Area (as defined in the
       Lease to which this is Exhibit "D"). Basic Costs shall not include the
       cost of any capital improvements, depreciation, interest on principal
       payments on mortgage and other non-operating debts,(2) of Landlord. Basic
       Costs shall, however, include the amortization of capital improvements
       which are primarily for the purpose of reducing Basic Costs, or which are
       required by governmental authorities.

          3.  Base Rental Adjustment. Effective the first day following the
       expiration of each twelve (12) month period during the Lease Term, the
       Base Rental shall be adjusted as follows: Successive yearly base rates
       are one hundred four and one half percent (104.5%) of the previous year's
       Base Rental. Landlord shall be entitled to require that the payment of
       the adjustment to Base Rental provided for in this paragraph, be made in
       monthly installments equal to 1/12 of such adjustment for each year
       during the remainder of the Lease Term, such installments being due and
       payable on the first day of each calendar month during such Year. The
       Expense Stop initially stated in paragraph 1(a) hereof shall be utilized
       throughout the term of this Lease for the purpose of calculating the
       Excess pursuant to Paragraph 1(a) notwithstanding any adjustment to Base
       Rental pursuant to this paragraph.

TENANT:  Keyvan Rafie, a                  LANDLORD: Met Life International Real
sole proprietorship                       Estate Equity Shares. Inc., a Delaware
                                          corporation

By: /s/ KEYVAN RAFIE                      By: /s/ MICHAEL J. CURRAN
   -------------------------------           -------------------------------
       Keyvan Rafie                              Michael J. Curran
Title: A Sole Proprietorship              Title: Assistant Vice President
      ----------------------------               ---------------------------

Date:     5-18-92                         Date:         5/29/92
     -----------------------------             -----------------------------

       ---------------------

          (2) Marketing, other tenant improvements and leasing expenses.

<PAGE>   25

                                   EXHIBIT "E"

This Exhibit "E" is attached hereto and made a part of the Lease dated May 29
1992, by and between Met Life International Real Estate Equity Shares, Inc.,
("Landlord") and Keyvan Rafei, a sole proprietorship ("Tenant").

                              RULES AND REGULATIONS

1.     Sidewalks, doorways, vestibules, halls, stairways, and similar areas
       shall not be obstructed nor shall refuse, furniture, boxes or other items
       be placed therein by Tenant or its officers, agents, servants, and
       employees, or used for any purpose other than ingress and egress to and
       from the leased premises, or for going from one part of the Building to
       another part of the Building. Canvassing, soliciting and peddling in the
       Project are prohibited.

2.     Plumbing fixtures and appliances shall be used only for the purposes for
       which constructed, and no unsuitable material shall be placed therein.

3.     No signs, directories, posters, advertisements, or notices shall be
       painted or affixed on or to any of the windows or doors, or in corridors
       or other common areas of the Building, except in such color, size, and
       style, and in such places, as shall be first approved in writing by
       Landlord in its reasonable discretion. One building standard suite
       identification sign will be prepared by Landlord at Landlord's expense.
       No additional signs shall be posted without Landlord's prior written
       consent as to location and form, and the cost of preparing and posting
       such signs shall be borne solely by Tenant. Landlord shall have the right
       to remove all unapproved signs without notice to Tenant, at the expense
       of Tenant.

4.     Tenants shall not do, or permit anything to be done in or about the
       Building, or bring or keep anything therein, that will in any way
       increase the rate of fire or other insurance on the Building, or on
       property kept therein or otherwise increase the possibility of fire or
       other casualty.

5.     Landlord shall have the power to prescribe the weight and position of
       heavy equipment or objects which may overstress any portion of the floor.
       All damage done to the Building by the improper placing of such heavy
       items will be repaired at the sole expense of the responsible Tenant.

6.     Tenant shall notify the Building manager when safes or other heavy
       equipment are to be taken in or out of the Building, and the moving shall
       be done after written permission is obtained from Landlord on such
       conditions as Landlord shall require. Any moving in or moving out of
       Tenant equipment, furniture, files, and/or fixtures shall be done only
       with prior written notice to Landlord, and Landlord shall be entitled to
       prescribe the hours of such activity, the elevators which shall be
       available for such activity and shall, in addition, be entitled to place
       such other reasonable conditions upon Tenant moving activities as
       Landlord deems appropriate. Tenant shall bear all risk of loss relating
       to damage incurred with respect to Tenant's property in the process of
       such a move, and in addition, shall indemnify and hold Landlord harmless
       as to all losses, damages, claims, causes of action, costs and/or
       expenses relating to personal injury or property damage sustained by
       Landlord or any third party on account of Tenant moving activities.

7.     Corridor doors, when not in use, shall be kept closed.

<PAGE>   26
8.     All deliveries must be made via the service entrance and elevators,
       designated by Landlord for service, if any, during Normal Business Hours.
       Landlord's written approval must be obtained for any delivery after
       normal working hours.

9.     Each tenant shall cooperate with Landlord's employees in keeping leased
       premises neat and clean.

10.    Tenant shall not cause or permit any improper noises in the Building, or
       allow any unpleasant odors to emanate from the leased premises, or
       otherwise unreasonably interfere, injure or annoy in any way other
       tenants, or persons having business with them.

11.    No animals shall be brought into or kept in or about the Building.

12.    No boxes, crates or other such materials shall be stored in hallways or
       other Common Areas. When Tenant must dispose of crates, boxes, etc. it
       will be the responsibility of Tenant to dispose of same prior to, or
       after the hours of 7:30 a.m. and 5:30 p.m., respectively, so as to avoid
       having such debris visible in the Common Areas during Normal Business
       Hours.

13.    No machinery of any kind, other than ordinary office machines such as
       typewriters, calculators, and standard office equipment shall be operated
       on leased premises without the prior written consent of Landlord, nor
       shall a tenant use or keep in the Building any flammable or explosive
       fluid or substance (including Christmas trees and ornaments), or any
       illuminating materials, except candles. No space heaters or fans shall be
       operated in the Building.

14.    No bicycles, motorcycles or similar vehicles will be allowed in the
       Building.

15.    No nails, hooks or screws shall be driven into or inserted in any part of
       the Building except picture frames and as otherwise approved by Building
       maintenance personnel. Nothing shall be affixed to, or made to hang from
       the ceiling of the Premises without Landlord's prior written consent.

16.    Landlord has the right to evacuate the Building in the event of an
       emergency or catastrophe.

17.    No food and/or beverages shall be distributed from Tenant's office
       without prior written approval of the Building Manager.

18.    No additional locks shall be placed upon any doors without the prior
       written consent of the Landlord.

       All necessary keys shall be furnished by Landlord, and the same shall be
       surrendered upon termination of this lease, and Tenant shall then give
       Landlord or his agent an explanation of the combination of all locks on
       the doors or vaults. Tenant shall initially be given ten (10) keys to the
       Premises by Landlord. No duplicates of such keys shall be made by Tenant.
       Additional keys shall be obtained only from Landlord, at a fee to be
       determined by Landlord.
<PAGE>   27

19.    Tenant will not locate furnishings or cabinets adjacent to mechanical or
       electrical access panels so as to prevent operating personnel from
       servicing such units as routine or emergency access may require. Cost of
       moving such furnishings for Landlord's access will be for Tenant's
       account. The lighting and air conditioning equipment of the Building will
       remain the exclusive charge of the Building designated personnel.

20.    Tenant shall comply with parking rules and regulations as may be posted
       and distributed from time to time.

21.    No portion of the Building shall be used for the purpose of lodging
       rooms.

22.    Vending machines or dispensing machines of any kind will not be placed in
       the leased premises by Tenant.

23.    Prior written approval, which shall be at Landlord's sole discretion,
       must be obtained for installation of window shades, blinds, drapes, or
       any other window treatment of any kind whatsoever. Which approval will
       not be unreasonably withheld. Landlord will control all internal lighting
       that may be visible from the exterior of the Building and shall have the
       right to change any unapproved lighting, without notice to Tenant, at
       Tenant's expense.

24.    No Tenant shall make any material changes or alterations to any portion
       of the Building without Landlord's prior written approval, which may be
       given on such conditions as Landlord may elect which shall not be
       unreasonable. All such work shall be done by Landlord or by contractors
       and/or workmen approved by Landlord, working under Landlord's
       supervision.

25.    Landlord reserves the right to rescind any of these rules and make such
       other and further reasonable rules and regulations as in its reasonable
       judgment shall from time to time be needful for the subject to operation
       of the Building subject to the terms of this Lease, which rules shall be
       binding upon each Tenant upon delivery to such Tenant of notice thereof
       in writing.

<TABLE>
<S>                                       <C>
TENANT: Keyvan Rafie, a                    LANDLORD: Met Life International Real
sole proprietorship                        Estate Equity Shares, Inc., a Delaware
                                           corporation

By: /s/ KEYVAN RAFIE                       By: /s/ MICHAEL J. CURRAN      GG
   -------------------------                  -------------------------------
        Keyvan Rafie                               Michael J. Curran

Title: A Sole Proprietorship               Title: Assistant Vice President
      ----------------------                     ----------------------------

Date:      5-18-92                         Date:          5/29/92
     -----------------------                    -----------------------------
</TABLE>

<PAGE>   28

                                   EXHIBIT "F"

This Exhibit "F" is attached hereto and made a part of the Lease dated
May 29, 1992 by and between Met Life International Real Estate Equity
Shares, Inc., ("Landlord") and Keyvan Rafie, a sole proprietorship, ("Tenant").

                         PARKING SPACE RENTAL AGREEMENT

       This Agreement is made and entered into by and between MET LIFE
INTERNATIONAL REAL ESTATE EQUITY SHARES, INC., a Delaware corporation (herein
"Landlord") and Keyvan Rafie, a sole proprietorship, (herein "Tenant").

RECITALS:

       A.     Landlord is "Landlord" and Tenant is "Tenant" under that certain
Lease Agreement (the "Lease") dated May 29, 1992 wherein Tenant leased from
Landlord certain premises (the "Premises") located in Landlord's office building
(the "Building") at 8330 Boone Boulevard, Vienna, Virginia, 22182.

       B.     Landlord desires to grant and Tenant desires to acquire the right
to use certain of the Building's parking spaces.

       NOW, THEREFORE, for and in consideration of Ten and No/l00 Dollars,
($10.00) and other valuable consideration, the receipt and sufficiency of which
are hereby acknowledged, the parties hereto hereby agree as follows:

       1.     Landlord hereby grants Tenant license to use seventy-six (76)
parking spaces (the "Parking Spaces") located in the Building garage at no
additional expense to Tenant for the initial term of this Lease, for the purpose
of parking motor vehicles for a term commencing on July 1, 1992 and terminating
upon termination or expiration of the Lease for whatever reason.

       2.     In addition, Landlord hereby grants Tenant license to use fourteen
(14) parking spaces (the "Parking Spaces") located in the Building garage for
the initial term of this Lease, for the purpose of parking motor vehicles for a
term commencing on July 1, 1992 and terminating upon termination or expiration
of the Lease for whatever reason. Tenant hereby agrees to pay an initial rental
fee of $25.00 per month for each of the Parking Spaces, which fee shall be
payable monthly in advance on or before the first day of each month throughout
the initial term of the Lease.

       3.     All motor vehicles (including all contents thereof) shall be
parked in all spaces leased hereunder at the sole risk of the owner thereof, it
being expressly agreed and understood that Landlord has no duty to insure any of
said motor vehicles (including the contents thereof), and that Landlord is not
responsible for the protection and/or security of such vehicles. Landlord shall
have no liability whatsoever to Tenant for any

-----------------

       (3) Two (2) of the seventy six (76) parking spaces shall be reserved for
"Rafie & Associates".

<PAGE>   29

property damage and/or personal injury which might occur as a result of or in
connection with the parking of said motor vehicles in any of said spaces, and
Tenant hereby agrees to indemnify and hold Landlord harmless from and against
any and all costs, claims, expenses, and/or causes of action (including
reasonable attorney's fees) which Landlord may incur in connection with or
arising out of Tenant's use of said spaces pursuant to this Agreement.

       4.     It is further agreed that this Agreement shall not be deemed to
create a bailment between the parties hereto, it being expressly agreed and
understood that the only relationship created between Landlord and Tenant hereby
is that of licensor and licensee, respectively.

       5.     In its use of the spaces, Tenant shall follow all of the rules of
the Building applicable thereto, as the same may be reasonably amended from time
to time. Upon the occurrence of any breach of such rules, or default by Tenant
pursuant to Section 26 of this Lease, or under this Agreement, Landlord shall be
entitled to terminate this Agreement, in which event Tenant's right to utilize
any and all of the spaces leased hereunder shall thereupon cease.

       6.     In the event of substantial casualty damage to the parking garage
located within the Project (the "Garage") which in accordance with Section 23 of
this Lease makes it impossible or impractical for Landlord economically to
comply with this Agreement, this license shall terminate upon and as of the
date of such casualty. If the Garage (or a portion thereof) or any part of the
real property upon which the Garage is situated is taken by governmental or
quasi-governmental action or sale in lieu thereof and such taking or sale makes
it impractical or impossible for Landlord economically to comply with this
Agreement, this Agreement shall terminate as of the date of such taking or sale.

       7.     To further insure that only those parties leasing Parking Spaces
are utilizing such parking spaces, Tenant shall provide Landlord with a complete
list of the names of all of Tenant's employees issued security access cards,
which list shall contain the corresponding license plate numbers of those
automobiles owned, leased or used by each of said employees. Such list shall be
updated by Tenant periodically, as necessary, and shall contain a specific
designation as to which automobiles of which employees have been issued decals
for Parking Spaces. Tenant hereby agrees to pay all amounts falling due
hereunder upon demand therefore, and the failure to pay any such amount shall
additionally be deemed an event of default under the Lease, entitling Landlord
to all of its right and remedies thereunder.

TENANT: Keyvan Rafie, a              LANDLORD: Met Life International Real
sole proprietorship                  Estate Equity Shares, Inc., a Delaware
                                     corporation

By: /s/ KEYVAN RAFIE                 By: /s/ MICHAEL J. CURRAN         GG
   --------------------------            ---------------------------------
        Keyvan Rafie                             Michael J. Curran

Title: A Sole Proprietorship        Title: Assistant Vice President
      -----------------------              -------------------------------

Date:       5-18-92                 Date:          5/29/92
     ------------------------              -------------------------------

<PAGE>   30
                                   EXHIBIT "G"

                               TERMINATION OPTION

Tenant shall have the one (1) time option to terminate this Lease on the last
day of the ninety-sixth (96th) month of the Lease Term provided that (i) Tenant
is not then nor has ever been in material default of any of the terms and
conditions under this Lease, (ii) Tenant provides Landlord with at least two
hundred seventy (270) days prior written notice of such termination, and (iii)
Tenant shall pay a cash termination fee equal to $300,000.00 (representing
unamortized costs (i.e., above standard improvements, commissions and rental
concessions)) submitted with written notice. In the event Tenant is not in
default of any of the obligations of this Lease and Tenant does not exercise
this Option to Terminate under the terms and conditions mentioned above,
Tenant's lease shall remain in full force for the remainder of the Lease Term.

<TABLE>
<S>                                        <C>
TENANT: Keyvan Rafie, a                     LANDORD: Met International Real
sole proprietorship                         Estate Equity Shares, Inc., a Delaware
                                            corporation

By: /s/ KEYVAN RAFIE                        By /s/ MICHAEL J. CURRAN       GG
    -----------------------------              ---------------------------------
            Keyvan Rafie                               Michael J. Curran

Title: A Sole Proprietorship                Title: Assistant Vice President
      ---------------------------                 ------------------------------

Date:        5-18-92                        Date:         5/29/92
     ----------------------------                -------------------------------
</TABLE>

<PAGE>   31
                                   EXHIBIT "H"

                                 EXPANSION SPACE

Tenant shall have the following rights to lease additional space in the
Building, subject to the following term and conditions:

1.     The Expansion Space

       (A)    Tenant shall have the right to lease a block of approximately
5,000 s.f. square feet [plus or minus twenty percent (20%)] of Net Rentable Area
in the Building ("The Expansion Space"). The Expansion Space shall be made
available to Tenant no earlier than the first day of the forty-eighth (48th)
month of the Lease Term and no later than the last day of the seventy-second
(72nd) month of the Lease Term. On or before the first day of the thirty-sixth
(36th) month of the Lease Term, Landlord shall provide Tenant with a written
notice stating: (i) the exact location of The Expansion Space (to be
cross-hatched on a floor plan of the Building); (ii) the exact Net Rentable Area
of The Expansion Space that will be available; and (iii) the date during The
Expansion Period that The Expansion Space will be available for Tenant's
occupancy ("The Expansion Space Availability Date"). Tenant shall provide
Landlord with written notice of its election to exercise this option, or its
rejection thereof, at least nine (9) months prior to The Expansion Space
Availability Date. Tenant hereby agrees that it will act reasonably with respect
to Landlord's ability to deliver the exact square footage described above for
The Expansion Space.

       (B)    The annual base rental payable for The Expansion Space shall be at
the prevailing market rate of comparable space in the building as of The
Expansion Space Availability Date.

       (C)    Within seven (7) days following Tenant's exercise of its option to
lease The Expansion Space, Landlord and Tenant shall execute an amendment ("The
Amendment") to this Lease incorporating The Expansion Space into the Premises,
and setting forth the provisions contained in Subparagraph 1(B) above. Tenant's
failure to execute The Amendment within such seven (7) day period for any reason
other than Landlord's failure to provide such Amendment to Tenant, shall
constitute a waiver of the option granted in this Section 1.

<PAGE>   32

2.     Improvements

       In the event Tenant's Expansion Space has either: (i) never been built
out; or (ii) demolished for whatever reason, the Landlord shall provide Tenant
a Building Standard work letter consistent with Exhibit "C" attached hereto. In
the event Tenant's Expansion Space has been previously built out for office use,
then Tenant shall accept said Expansion Space in it's present "as is" condition.

<TABLE>
<S>                                        <C>
TENANT: Keyvan Rafie, a                     LANDLORD: Met Life International Real
sole proprietorship                         Estate Equity Shares, Inc., a Delaware
                                            corporation

By: /s/ Keyvan Rafie                        By: /s/ Michael J. Curran         GG
    ------------------------                    --------------------------------
         Keyvan Rafie                                  Michael J. Curran

Title: A Sole Proprietorship                Title: Assistant Vice President
       ---------------------                      ------------------------------

Date:       5-18-92                         Date:       5/29/92
      ----------------------                     -------------------------------
</TABLE>

<PAGE>   33

                                   EXHIBIT "I"

                                 RENEWAL OPTION

Tenant shall have the following option (the "Option") to renew this Lease:

Tenant may, by notifying Landlord of it's election in writing at least twelve
(12) months prior to the end of the Lease Term, renew this Lease for an
additional lease term (the "Second Lease Term") beginning on the day next
following the expiration date of the Lease Term and continuing for five (5)
years thereafter. Such renewal shall be on all of the terms and conditions of
this Lease which are not inconsistent herewith, except that the rentals payable
during the Second Lease Term shall be at the then prevailing market rental rate
of comparable space within the Building as of the date of renewals, less five
percent (5 %). In no event, however, shall the rental rate for the Second Lease
Term be less than the rental rate for the Initial Lease Term.

Failure by Tenant to notify Landlord of Tenant's election to exercise this
renewal option herein granted within the time limited set forth for such
exercise shall constitute a waiver of such Option.

For the purposes of determining the prevailing market rate of the Premises (the
"Market Rate") for the renewal terms, Landlord and Tenant agree to the following
procedure:

       (i)    The Market Rate shall be determined by Landlord and Tenant during
the period of the first three months following Tenant's notice to Landlord that
Tenant elects to exercise its option to extend the Lease for a renewal term; and

       (ii)   In the event Landlord and Tenant are unable to agree upon the
Market Rate of the Premises during said three month period; then the same shall
be determined by arbitration in the following manner:

              FIRST: Landlord and Tenant shall each appoint a fit and impartial
       person as arbiter who shall have had at least ten (10) years of
       experience in the County Fairfax in a calling connected with the subject
       matter of the dispute. Such appointment shall be signified in writing by
       each party to the other, and the arbiters so appointed, in the event of
       their failure to agree within thirty (30) days upon the matter so
       submitted, shall appoint an umpire.

              SECOND: In the case of failure of such arbiters to agree and their
       failure to agree upon an umpire, then such umpire shall be appointed by
       the American Arbitration Association from its qualified panel of
       arbitrators, and shall be a person having at least ten (10) years
       experience as to the subject matter in question.

              THIRD: In case either Landlord or Tenant shall fail to appoint an
       arbiter, as aforesaid, within a person of twenty (20) days after written
       notice from the other party to make such appointment, than the arbiter
       appointed by the party no in default hereunder shall appoint a second
       arbiter and the two so appointed shall, in the event of their failure to
       agree upon a decision within ten (10) days thereafter, appoint an umpire.

<PAGE>   34

              FOURTH: The arbiters and umpire, after being duly sworn to perform
       their duties with impartiality and fidelity, shall proceed with all
       reasonable dispatch to determine the questions submitted. The decision of
       the arbiters and umpire, as the case may be, shall in any event be
       rendered within thirty (30) days after their appointment, and such
       decision shall be in writing and in duplicate, one counterpart thereof to
       be delivered to each of the parties.

              FIFTH: The arbitration shall be conducted in accordance with the
       rules of the American Arbitration Association, and the award of the
       arbitrators shall be binding, final and conclusive on the parties. The
       fees of the arbiters and umpire and the expenses incident to the
       proceedings shall be borne equally between Landlord and Tenant. The fees
       of respective counsel engaged by the parties, and the fees of expert
       witnesses and other witnesses called for by the parties shall be paid by
       the respective party engaging such counsel or calling or engaging such
       witnesses.

              SIXTH: The arbiters and umpire, as the case may be, shall have not
       authority to modify, change or amend any of the terms, covenants and
       conditions of this Lease, and shall be limited to making a determination
       of the then Market Rate of the Premises.

TENANT: Keyvan Rafie, a                   LANDLORD: Met Life International Real
sole proprietorship                       Estate Equity Shares, Inc., a Delaware
                                          corporation

By: /s/ KEYVAN RAFIE                      By: /s/ MICHAEL J. CURRAN       GG
   -------------------------------           -------------------------------
        Keyvan Rafie                             Michael J. Curran
Title:  A Sole Proprietorship             Title: Assistant Vice President
      ----------------------------               ---------------------------

Date:     5-18-92                         Date:         5/29/92
     -----------------------------             -----------------------------

<PAGE>   35

                                   EXHIBIT "J"

                               INDEMNITY AGREEMENT

THIS INDEMNITY AGREEMENT (this "Agreement") is made as of the 29th day of May,
l992 by and between MET LIFE INTERNATIONAL REAL ESTATE EQUITY SHARES, INC., a
Delaware corporation ("Landlord"), and KEYVAN RAFIE, a sole proprietorship
("Tenant").

                                    Recitals:

R-1. Landlord, as landlord, and Tenant, as tenant, have entered into a certain
lease (the "Lease") dated of even date herewith covering certain premises more
particularly described in Exhibit "B" of the Lease in the building located at
8330 Boone Boulevard, Vienna, in Fairfax, Virginia.

R-2. Tenant is currently party as tenant to that certain office Lease (also
referred to in said Office Lease as the "Standard Office Lease" and the
"Agreement of Lease", but herein referred to as the Tycon Lease) dated the 30th
day of November 1987, by and between Tenant and J.T.L. Tycon Towers I Limited
Partnership ("J.T.L."), a Virginia Limited Partnership, as landlord, covering
premises (the "Tycon Premises") known as Suite 1300 in the building located at
8000 Towers Crescent Drive, Vienna, Virginia, as amended by Lease Addendum dated
the 30th day of November, 1987.

R-3. To induce Tenant to enter into the Lease, Landlord has agreed to indemnify
Tenant from liability for monthly rent and its proportionate share of operating
costs and expenses under the Tycon Lease from and after the later to occur (the
"Indemnity Commencement Date") of (i) the commencement date of the Lease or (ii)
the date Tenant vacates the Tycon Premises, subject to the terms and conditions
of this Agreement.

R-4. The parties desire to enter into this Agreement to set forth their
respective rights and obligations with respect to the Tycon Lease.

NOW, THEREFORE, in consideration of the premises, the mutual covenants and
agreements of the parties, and for other good and valuable consideration, the
receipt and sufficiency of which are hereby acknowledged, the parties undertake
as follows:

                                   Agreement:

1.     Recitals. The foregoing Recitals are a material part of this Agreement
and are incorporated herein by reference.

2.     Indemnity. Subject to compliance by Tenant with all of its obligations
under this Agreement and the Lease, Landlord hereby indemnifies and holds
harmless Tenant from and against its obligations under the Tycon Lease, coming
due subsequent to the Indemnity Commencement Date, to pay the monthly rent and
the Tenant's proportionate share of operating costs and expenses under the Tycon
Lease, less the amount of any payments made by any subtenant or assignee on
account of such rent or other charges. Notwithstanding that Landlord may from
time to time make payments of rent due under the Tycon Lease directly to J.T.L.
on behalf of Tenant, such payments shall not be construed, nor shall the same be
deemed, as an assumption of, nor of Landlord's intent or desire to assume, nor
as an acceptance of an assignment by Tenant of, the Tycon Lease.

<PAGE>   36

3.     Management Agent.

       (a)    Tenant hereby appoints Landlord as Tenant's agent for the purpose
of locating and entering into subleases or assignments of all or portions of the
Tycon Premises, and for the purposes of acting as Tenant's managing agent for
the collection of sub-rents and other payments due under any subleases and
assignments enforcement of subleases and assignments, and taking such action as
may be necessary under any sublease or assignment in furtherance of performance
hereunder. Landlord hereby accepts such appointment.

       (b)    Upon request by Landlord, Tenant shall provide written notice to
J.T.L. and its managing agent of the appointment by Tenant of Landlord as its
agent for the purposes described herein.

       (c)    It is the intent of the parties that Landlord shall have the right
to manage and control the Tycon Premises and the subleasing and assignment
thereof, and have full and complete information with respect to such premises
and their use and occupancy, in order that Landlord shall have all opportunity
to mitigate and control its indemnity obligations. Any action or omission by
Tenant which is inconsistent with such intent (including without limitation
direct dealings with any subleases or assignee without Landlord's approval, or
termination of this agency) shall upon five (5) business days written notice
discharge Landlord from its obligations under this Agreement.

4.     Condition of Premises. Until the commencement date of the Lease, Tenant
will maintain the Tycon Premises in a good and orderly condition, in compliance
with all terms of the Tycon Lease, and shall not remove therefrom any bathroom
fixtures, lighting fixtures, finishes, millwork, floor covering and similar
items, without the prior written consent of Landlord, which consent may be
granted or withheld by Landlord in its discretion. As soon as is reasonably
possible after the commencement date of the Lease, Tenant will vacate the Tycon
Premises, leaving the same vacant or Tenant's personal property and equipment,
in broom-clean condition, and in condition suitable for showing to prospective
subtenants or assignees thereof.

5.     Cooperation.

       (a)    Tenant shall cooperate with and assist Landlord in effecting an
assignment of subletting of all or portions of the Tycon Premises to assignee(s)
or subtenant(s) identified by Landlord, including without limitation, assistance
in obtaining such consents as may be necessary from J.T.L., its agents,
successors or assigns, and providing access for the purpose of showing the Tycon
Premises to prospective assignees and subtenants.

       (b)    Within five (5) business days after request therefor by Landlord,
Tenant shall execute such assignments and/or subleases to assignee(s) and
subtenant(s) identified by Landlord, it being understood that, as between Tenant
and Landlord, Tenant, unless this Agreement is terminated as herein provided,
shall not be responsible for fulfilling any economic obligations in the nature
of inducements in connection with any such assignment or sublease. The parties
agree that the form of assignment attached hereto as Exhibit "A" and the form of
sublease attached hereto as Exhibit "B", with such modifications as may be
necessary to implement a particular transaction, are acceptable.

       (c)    In the event Tenant receives any notices from any assignee or
subtenant, it shall immediately provide copies thereof to Landlord. Tenant shall
not deliver any notices or other communications to any assignee or subtenant
without prior approval of or being requested to do so by Landlord.

<PAGE>   37

       (d)    Any sublease or assignment payments made to Tenant shall be
forthwith remitted to Landlord.

       (e)    In the event Tenant acquires knowledge of any default of
threatened default of any assignee or subtenant, it shall promptly advise
Landlord of the nature and circumstances thereof, to the full extent of Tenant's
knowledge.

6.     Lease Status. Tenant will fully comply with and keep the Tycon Lease in
full force and effect. Tenant will promptly provide Landlord with copies of all
notices and other communications from J.T.L., its agents, successors or assigns,
and shall deliver such notices and take such action with respect thereto as
Landlord may direct. Without limiting the generality of the foregoing, all
notices and statements of any increases in operating costs and expenses and
other notices of any change in terms, conditions or operations shall be timely
delivered promptly. Landlord shall have the right, by notice to Tenant, to cause
Tenant to exercise any of its rights any remedies under the Tycon Lease,
including without limitation the right of audit statements to operating costs
and expenses and the right to exercise options to renew. Provided Tenant
complies with provisions outlined above and Tenant provides Landlord with
adequate notice of monetary obligation Landlord shall incur the expenses of
compliance.

7.     Representations. Tenant represents and warrants to Landlord, as a
material inducement for Landlord entering into this Agreement, that as of the
date of this Agreement:

       (a)    The Tycon Lease is in full force and effect and there exists no
default thereunder by any party which, with the giving of notice or the passage
of time, would entitle any party to terminate the same;

       (b)    Attached hereto as Exhibit "C" is a true and complete copy of the
Tycon Lease, with all amendments and modifications thereof;

       (c)    Except as set forth in Exhibit "C", the Tycon Lease has not been
modified or amended;

       (d)    Attached hereto as Exhibit "D" are true and complete copies of all
notices, communications, statements of operating costs and expenses and
adjustments of rent, audit reports, and all other written materials received
from J.T.L. and its managing agent in Tenant's possession;

       (e)    Attached hereto as Exhibit "E" are true and complete records of
Tenant's share and amounts of operating costs and expenses passed through to
Tenant under the Tycon Lease.

8.     Rent Prior to Indemnity Commencement. In all events Tenant shall be
responsible for payment of all rent and its proportionate share of operating
costs and expenses accrued under the Tycon Lease until the Indemnity
Commencement Date. Such payments shall be made to as specified in the Tycon
Lease and in accordance therewith, and Tenant shall provide Landlord with
reasonably satisfactory documentary evidence of such payment.

9.     Termination; Discharge. Landlord shall be discharged from its indemnity
obligations hereunder, and this Agreement shall terminate, upon (a) any breach
by Tenant of the Lease and the exercise of any remedies thereunder and failure
to cure any such breach within the applicable notice provisions; (b) any breach
by Tenant of its obligations hereunder, or (c) any termination of the Tycon
Lease; provided that Landlord is not responsible for such Termination.

<PAGE>   38
10.    No Third-Party Benefits. The provisions of this Agreement are as between
Landlord and Tenant only and no third party (including without limitation
J.T.L., its managing agent, and its successors and assigns) is intended to be
benefitted hereby.

11.    Independent Covenants. Except to the extent that a breach of the Lease
may operate to terminate this Agreement under subclause (a) of Paragraph 9
above, the covenants and undertakings of the parties set forth herein are
independent of the obligations of the parties under the Lease, and the covenants
and undertakings of the parties set forth in the Lease are independent of the
obligations of the parties under this Agreement.

12.    Notices. All notices permitted or required to be given hereunder shall be
effective upon delivery in the manner and to the parties as provided in the
Lease.

13.    Governing Law. This Agreement is intended to be performed in the
Commonwealth of Virginia and shall be governed by the substantive laws of such
jurisdiction.

14.    Waiver of Jury Trial. In the event of any dispute under this Agreement,
the parties desire that such dispute be tried as to factual matters by a judge,
and not by a jury. Accordingly, each party hereto fully and freely waives trail
by jury in any action, proceeding or counterclaim brought or asserted by either
of the parties hereto against the other.

15.    Assignment. This Agreement is personal between the parties. Tenant shall
not assign any of its rights or obligations under this Agreement without the
written consent of Landlord; any attempted assignment shall be void without such
consent, and shall further constitute a breach of Tenant's obligations
hereunder, terminating Landlord's obligations under this Agreement.

16.    Modifications and Waivers. No modifications, waiver, amendment, or change
of this Agreement, except as otherwise provided herein, shall be valid unless
the same is in writing and signed by the party against which the enforcement of
such modification, waiver, amendment, or change is sought. This Agreement
contains the entire agreement between the parties relating to the subject matter
hereof, and all prior or contemporaneous agreements, understandings,
representations and statements, oral or written, are merged herein.

17.    Exhibits. All exhibits referred to herein and attached hereto are
incorporated by reference into this Agreement.

18.    Construction. Each party hereto and its counsel has reviewed and revised
(or requested revisions of) this Agreement, and the normal rule of construction
that any ambiguities are to be resolved against the drafting party shall not be
applicable in the construction and interpretation of this Agreement.

19.    Captions. The captions of this Agreement are inserted for convenience of
reference only and do not define, describe or limit the scope or the intent of
this Agreement or any term hereof.

<PAGE>   39

20.    Counterparts; Form of Execution. This Agreement may be executed in any
number of counterparts, each of which shall be deemed to be an original, but all
of which together shall constitute one and the same instrument.

IN WITNESS WHEREOF, the parties have caused this Agreement to be executed by
persons duly authorized to bind them to their respective obligations hereunder.

WITNESS:                              MET LIFE INTERNATIONAL REAL ESTATE EQUITY
                                      SHARES, INC., a Delaware corporation

                                      By: /s/ Michael J. Curran         GG
                                         -----------------------------------
                                              Michael J. Curran,

                                      Title: Assistant Vice President
                                            --------------------------------
                                      Date:  5/29/92
                                            --------------------------------

  /s/ Gail E. Griffith
---------------------------

Name: Gail Griffith
     ----------------------
Date:    5-29-92
     ----------------------

WITNESS:                              KEYVAN RAFIE, a sole proprietorship

                                      By: /s/ Keyvan Rafie
                                         ----------------------------------
                                                   Keyvan Rafie

                                      Title:    A Sole Proprietorship
                                            -------------------------------
                                      Date:       5-18-92
                                            -------------------------------

  /s/ Alexandria P. West
----------------------------

Name: Alexandria P. West
     -----------------------

Date:       5-18-92
     -----------------------

<PAGE>   40

                                LIST OF EXHIBITS

<TABLE>
<S>                     <C>     <C>
Exhibit "A"             -       Form of Assignment

Exhibit "B"             -       Form of Sublease

Exhibit "C"             -       Complete copy of the Lease with all attachments

Exhibit "D"             -       Copies of all: notices; communications; statements of operating costs
                                and adjustments of rent; audit reports; and all other written
                                materials received from J.T.L. and its managing agent.

Exhibit "E"             -       Complete records of Tenant's share and amounts of operating costs
                                and expenses passed through to Tenant under the Tycon Lease.
</TABLE>

<PAGE>   41

                                   EXHIBIT "A"

          of Indemnity Agreement by and between Met Life International
      Real Estate Equity Shares, Inc. and Keyvan Rafei dated, May 29, 1992.

                     (PARTIAL) ASSIGNMENT AND ASSUMPTION OF
                          LESSEE'S INTEREST UNDER LEASE

This (Partial) Assignment and Assumption of Lessee's Interest Under Lease (the
"Assignment") is entered into as of this _____ day of __________, 1992, but
effective for all purposes as of __________,1992 (the "Effective Date"), by and
between Keyvan Rafei ("Assignor") and ______________________,("Assignee").

                                    RECITALS

       R-l.   Assignor is currently party as tenant to that certain Office Lease
(also referred to in said Office Lease as the "Standard Office Lease" and the
"Agreement of Lease", but herein referred to as the "Tycon Lease") dated the
30th day of November, 1987, by and between Assignor and J.T.L. Tycon Towers I
Limited Partnership ("J.T.L."), a Virginia Limited Partnership, as Landlord,
covering premises (the "Tycon Premises") known as Suite 1300 in the building
located at 8000 Towers Crescent Drive, Vienna, Virginia, as amended by Lease
Addendum dated the 30th day of November, 1987. A true copy of the Tycon Lease is
attached hereto as Exhibit A.

       R-2.   Assignor desires to assign to Assignee (the below-described
portion of) its right, title and interest in and to the Tycon Lease and the
Tycon Premises (the "Assigned Interest") upon the terms and conditions hereunder
set forth.

       R-3.   Assignee desires to accept such assignment and to assume the
obligations of Assignor as tenant with respect to the Assigned Interest, and to
be bound in Assignor's stead to the terms of the Tycon Lease with respect to the
Assigned Interest.

       NOW, THEREFORE, in consideration of the mutual promises and covenants
herein contained and other good and valuable consideration, the receipt and
sufficiently of which are hereby acknowledged, the parties agree as follows:

       1.     The above recitations, which are incorporated herein by this
reference, are true and correct.

       2.     Assignor hereby assigns, sets over and transfers unto Assignee
(all of its right, title and interest in and to the Tycon Lease) (a portion of
its right, title and interest in and to the Tycon Premises and the Tycon Lease,
more particularly described as follows:) (IF PARTIAL ASSIGNMENT, DESCRIBE TERM
OR PORTION OF PREMISES AND/OR LEASEHOLD BEING ASSIGNED).

<PAGE>   42

       3.     Assignee hereby accepts the foregoing assignment and the Assigned
Interest and to assume the obligations concomitant therewith, and covenants and
agrees to be bound by all of the terms, covenants and conditions of the Tycon
Lease, and to hold Assignee harmless from any loss or cost whatsoever arising
from or relating to a breach by Assignee of the foregoing covenant, subject only
to the following:

(LIST ANY OBLIGATIONS OF TENANT UNDER TYCON LEASE WHICH WILL NOT BE ASSUMED BY
ASSIGNEE)

       4.     All exhibits attached hereto are by this reference incorporated
herein to the same effect as if fully set forth herein.

       5.     This Assignment contains the entire agreement of the parties
hereto; all other agreements and understandings, whether oral or written, are
hereby merged into this Assignment and are of no force or effect except as so
merged.

       IN WITNESS WHEREOF, Assignor has executed this Assignment in the presence
of the undersigned witness as of the day and year first above-written, and
Assignee has caused this Assignment to be executed by _____________, its
____________, and its corporate seal to be hereunder affixed and attested by
____________________, its (Assistant) Secretary, and Assignee does hereby
appoint the said ______________ and ________________ as its true and lawful
attorney-in-fact to execute and deliver this Assignment as Assignee's act and
deed as of the day and year first above-written.

<TABLE>
<S>                                    <C>
                                        ASSIGNOR:

WITNESS:                                KEYVAN RAFEI

          [SIG]                          /s/ KEYVAN RAFEI
---------------------------             --------------------------------
Name                                    Keyvan Rafei

Date: 5/28/92                           Date: May/28/92
     ----------------------                  ---------------------------

ATTEST:                                 ASSIGNEE:

                                        --------------------------------

---------------------------
Name
                                        By:
                                           -----------------------------
Date:
     ----------------------
                                        Title:
                                              --------------------------

(Corporate Seal)                        Date:
                                             ---------------------------
</TABLE>

<PAGE>   43

                                   EXHIBIT "B"

            of Indemnity Agreement dated May 29, 1992 by and between
          Met Life International Equity Shares, Inc. and Keyvan Rafei

                               SUBLEASE AGREEMENT

     THIS SUBLEASE AGREEMENT, made and entered into this ___ day of __________,
1992, between ___________________, ("Tenant") and  ________________,
("Subtenant").

                                   WITNESSETH:

     WHEREAS, Tenant is in rightful possession of the premises known as
__________________ located at __________, designated as the ________ floor,
under the __________________ Lease Agreement dated, __________, a copy of which
Lease is attached hereto, marked as Exhibit "A" and made a part of this
Sublease Agreement; and

       WHEREAS, Tenant wishes to sublease Suite __ of the above premises to the
Subtenant on the terms stated herein;

       NOW, THEREFORE, in consideration of the premises and mutual covenants
contained herein, the parties agree as follows:

1.     PREMISES

       The Tenant hereby subleases to the Subtenants, and the Subtenant hereby
hires and leases from the Tenant, approximately _______ square feet of the
premises described in the Lease marked as Exhibit "A" which is herein
referred to as the "Subleased Premises".

 2.    TERM

       The term of the Sublease shall be for a period of___________ months
commencing on _________ and ending on ____________.

 3.    RENT

       Rent for the first year is to be __________________ per month payable on
the first (1st) day of each month. In addition, Subtenant agrees to pay to
Tenant the first (1st) month's rent in full immediately upon execution of this
Sublease Agreement. The rent for the second (2nd) year of the Sublease shall be
increased by ___  percent requiring payment of _______________ per month. There
shall be a four percent (4%) late charge for rent not received on or prior to
the due date for each month's rent.
<PAGE>   44

4.     ALTERATIONS

       The Subtenant may not modify the building design of the Subleased
premises without prior written approval by Tenant, which approval shall not be
unreasonably withheld. Subtenant must additionally coordinate any such building
design modification with ____________________, ("Landlord"). Subtenant shall be
solely responsible for the expense of any approved building design
modifications. Sublessee reserves the right to modify the existing suite entry,
with appropriate Landlord approval. Sublessor shall not be required to return
the suite to its original condition for approved alterations.

5.     PARKING

       During the term of this Sublease and during any extension of this
Sublease, Subtenant shall have the license to use ________ parking spaces in the
building garage at no charge.

                                       SUBLESSOR:

                                       BY:
                                          -------------------------------

                                       TITLE:
                                             ----------------------------

                                       DATE:
                                            -----------------------------

                                       SUBLESSEE:

                                       BY:
                                          -------------------------------

                                       TITLE:
                                             ----------------------------

                                       DATE:
                                            -----------------------------

                               CONSENT OF LANDLORD

       The undersigned is the Landlord under the within described Lease. The
undersigned hereby consents to this Assignment and expressly releases
_______________ from any further liability or obligation as Tenant under the
terms of the Lease.

                                       LANDLORD:

                                       BY:
                                          ------------------------------

                                       TITLE:
                                             ---------------------------

                                       DATE:
                                            -----------------------------<PAGE>   1

                                                                  EXHIBIT 10.14

                        AMERICAN CENTER LEASE AGREEMENT

      THIS DEED OF LEASE (the "Lease") is made and entered into as of the 27
day of September, 1997, between MET LIFE INTERNATIONAL REAL ESTATE EQUITY
SHARES, INC., a Delaware corporation ("Landlord"), and ADVANCED SWITCHING
COMMUNICATIONS, INC., a Delaware corporation ("Tenant").

                                    RECITALS

      A.     Landlord is the owner of an office complex (the "Complex") known
as "American Center", located at 8300 and 8330 Boone Boulevard, Vienna,
Virginia.

      B.     Tenant desires to lease certain space in the building located at
8330 Boone Boulevard (the "Building") in the Complex, and Landlord is willing
to lease such space to Tenant, upon the terms, conditions, covenants and
agreements set forth herein.

      NOW, THEREFORE, in consideration of the mutual promises herein contained
and other good and valuable consideration, the receipt and sufficiency of which
are hereby acknowledged, the parties hereto, intending legally to be bound,
hereby covenant and agree as follows.

                                   AGREEMENT

      1.     DEFINITIONS.

      (a)    "Premises" shall mean the space outlined on the floor plan
attached to this Lease as Exhibit A incorporated herein. The Premises are
stipulated for all purposes to contain approximately 20,914 square feet of "Net
Rentable Area" (as hereinafter defined) on the fifth floor of the Building;
provided, however, that Landlord may, upon completion of the Premises, cause
precise measurements of the Complex and the Premises to be made, and Base Rent
(as hereinafter defined) shall be adjusted upward or downward accordingly. The
Premises will be occupied in two phases: (i) approximately 13,262 square feet
of Net Rentable Area (the "Phase I Space") as shown on Exhibit A on the "Phase
I Commencement Date" (as hereinafter defined) and (ii) approximately 7,652
square feet of Net Rentable Area (the "Phase II Space") as shown on Exhibit A
on the "Phase II Commencement Date" (as hereinafter defined).

      (b)    "Base Rent" shall mean the fixed rent paid monthly during the
Lease Term as provided in the following schedule, which schedule reflects an
annual rent for the first Lease Year based on Twenty-Six and 75/100 Dollars
($26.75) per rentable square foot of Net Rentable Area of the Premises and
annual increases equal to three percent (3%) of the Net Base Rent in effect
during the immediately preceding Lease Year. As used herein, "Net Base Rent" is
the product of the Net Rentable Area times the difference between $26.75 and
the amount per square foot of the Operating Expenses for the Base Year. For
example, if the Operating Expenses for the Base Year are $7.50 per square foot,
then the monthly Net Base Rent would be $33,549.54 (i.e., $19.25 [$26.75 less
$7.50] times 20,914 sq. ft. divided by 12). The monthly Base Rent for the First
Lease Year will be $46,620.79 (i.e., $26.75 times 20,914 sq. ft. divided by
12); however, such amount shall be prorated until the Phase II Commencement
Date since Tenant

<PAGE>   2

will be initially be occupying only the Phase I Space. The monthly Base Rent
for the second Lease Year would be $47,627.28, an increase of $1,006.49 (i.e.,
monthly Net Base Rent of $33,549.54 times 3%). The monthly Base Rent for the
third Lease Year would be $48,663,96, an increase of $1,036.68 (i.e., monthly
Net Base Rent in effect during the immediately preceding Lease Year of
$34,556.03 [$33,549.54 plus $1,006.49] times 3%).

      (c)    "Phase I Commencement Date" and the "Phase II Commencement Date"
shall mean the dates determined in accordance with Section 3 hereof.

      (d)    "Lease Term" shall mean a term commencing on the Phase I
Commencement Date and continuing until ninety-six (96) calendar months after
the first day of the first full month following the Phase I Commencement Date.

      (e)    "Lease Year" shall mean that period beginning on the Phase I
Commencement Date and terminating on the last day of the twelfth (12th) full
calendar month thereafter, and each succeeding period of twelve (12) full
calendar months during the entire Lease Term.

      (f)    "Operating Expenses" shall mean the expenses described in Section
5(b) of this Lease.

      (g)    "Base Year" shall mean the 1998 calendar year for purposes of
determining increases in Operating Expenses pursuant to Section 5 of this
Lease.

      (h)    "Security Deposit" shall mean the sum of One Million and no/100
dollars ($1,000,000.00) in the form of a letter of credit or cash. The Security
Deposit has been deposited with Landlord by Tenant within 12 Business days of
the execution hereof.

      (i)    "Common Areas" shall mean those areas devoted to lobbies,
corridors, all elevator foyers, restrooms, mechanical rooms, janitorial
closets, electrical and telephone closets, vending areas and other similar
facilities provided for the common use or benefit of tenants generally and/or
the public.

      (j)    "Service Area" shall mean those areas within the outside walls of
the Complex used for elevator mechanical rooms, building stairs, fire towers,
elevator shafts, flues, vents, stacks, pipe shafts, and vertical ducts (but
shall not include any such areas for the exclusive use of the particular
Tenant).

      (k)    "Net Rentable Area" of the Premises shall mean the gross area
within the inside surface of the outer glass or other material comprising the
exterior walls of the Premises, to the mid-point of any walls separating
portions of the Premises from those of adjacent tenants and to the Common Area
or Service Area side of walls separating the Premises from Common Areas and
Service Areas, subject to the following:

             (1)    Net Rentable Area shall not include any Service Areas.

                                       2
<PAGE>   3

             (2)    Net Rentable Area shall include a pro rata part of the
Common Areas on the floor on which the Premises are located, such proration
based upon the ratio of the Net Rentable Area within the Premises to the total
Net Rentable Area on such floor, both determined without regard to the Common
Areas. The Common Area on floor(s) upon which the Premises are located shall
never exceed 2,735 square feet and may be adjusted as determined by Landlord
from time to time to confirm such allocation to changes in the configuration of
rented spaces and Common Areas upon such floor.

             (3)    Net Rentable Area shall include any columns and/or
projection(s) which protrude into the Premises and/or the Common Areas.

      (l)    "Exterior Common Areas" shall mean those areas of the Complex
which are not located within the buildings comprising the Complex and which are
provided and maintained for the common use and benefit of Landlord and tenants
of the Complex generally and the employees, invitees and licensees of Landlord
and such tenants; including without limitation all parking areas, enclosed or
otherwise; all streets, sidewalks and landscaped areas located within the
Complex.

      (m)    "Event of Default" shall have the meaning assigned thereto in
Section 26 of this Lease.

      2.     LEASE GRANT. Subject to and upon the terms herein set forth,
Landlord leases to Tenant, and Tenant leases from Landlord, the Premises. The
lease of the Premises includes the right, together with other tenants of the
Complex and members of the public, to use the Common Areas of the Building and
the Exterior Common Areas of the Complex, but includes no other rights not
specifically set forth herein. Landlord reserves the right to modify the size,
location, arrangement, finish and other features of the Common Areas and the
Exterior Common Areas.

      3.     LEASE TERM.

      (a)    The Lease Term shall commence on the Phase I Commencement Date and
shall continue until the expiration of the Lease Term unless this Lease is
terminated earlier or extended in accordance with the provisions of this Lease.

      (b)    The Phase I Commencement Date shall be the date on which Landlord
substantially completes construction of the tenant improvements in the Phase I
Space, as determined pursuant to Section 5 of Exhibit B attached hereto and
made a part hereof, or the date on which Tenant commences beneficial use of the
Phase I Space, whichever date occurs first. The Phase II Commencement Date
shall be the date on which Landlord substantially completes construction of the
tenant improvements in the Phase II Space, as determined pursuant to Section 5
of Exhibit B attached hereto and made a part hereof, or the date on which
Tenant commences beneficial use of the Phase II Space, whichever date occurs
first. Tenant shall be deemed to have commenced beneficial use of the Phase I
Space or the Phase II Space when

                                       3

<PAGE>   4

Tenant begins to move furniture and furnishings into the such space, and such
beneficial use shall be deemed to be an acceptance of the nature and sufficiency
of any tenant improvements to be made by Landlord with respect to the Phase I
Space and the Phase II Space. Notwithstanding the foregoing, if Landlord is
delayed in completing construction of the tenant improvements in the Phase I
Space or the Phase II Space as a result of any of the reasons described in
Exhibit B, then the Phase I Commencement Date or the Phase II Commencement Date
shall be the date determined in accordance with Section 7(f) of Exhibit B.

      (c)    Promptly after the Phase I Commencement Date and the Phase II
Commencement Date have been determined, Landlord and Tenant agree to execute a
written declaration in the form attached hereto as Exhibit C setting forth the
Phase I Commencement Date and the Phase II Commencement Date, as applicable,
and the date upon which the Lease Term will expire. Failure to sign said
written declaration shall not affect the commencement or expiration of the
Lease Term.

      (d)    It is presently anticipated that the Phase I Space will be ready
for occupancy by Tenant on or about December 1, 1997, and that the Phase II
Space will be ready for occupancy by Tenant on or about December 1, 1998. If
Landlord is unable to complete construction of the tenant improvements in, or
otherwise deliver possession of, the Phase I Space or the Phase II Space by
such dates, Landlord's liability to Tenant on account of Landlord's inability
to deliver possession thereof to Tenant shall be limited to the amount
specified in Section 7(g) of Exhibit B, and this Lease shall not be rendered
void or voidable as a result of such delay. If the tenant improvements have not
been substantially completed by the date referred to above due to omission,
delay or default by Tenant or anyone acting under or for Tenant, Landlord shall
have no liability because if such delays, and the obligations of this Lease
(including, without limitation, the obligation to pay rent) shall nonetheless
commence as of the Phase I Commencement Date or the Phase II Commencement Date
as applicable.

      (e)    Landlord shall have no obligation to deliver possession of the
Phase I Space or the Phase II Space to Tenant, and Tenant shall have no
obligation to accept delivery of the Phase I Space or Phase II Space from
Landlord, before the Phase I Commencement Date or the Phase II Commencement
Date, as applicable.

      (f)    Subject to the provisions of this subsection (f), Tenant shall
have, and is hereby granted, an option to renew or extend the Lease Term for
the entire Premises for one (1) additional period of sixty (60) months (such
additional period being hereinafter referred to as the "Renewal Term").

             i)     This renewal option shall be exercisable by Tenant by
      giving written notice to Landlord of Tenant's intention to exercise such
      renewal option not more than fourteen (14) months but no later than nine
      (9) months before the expiration of the initial Lease Term. If Tenant
      shall fail to exercise the renewal option at the time and in the manner
      hereinabove provided or should Tenant fail to execute an addendum to this
      Lease within thirty (30) days of the determination

                                       4

<PAGE>   5

of the Market Rent (as hereinafter defined), this option shall be rendered void
and of no force or effect, and Tenant shall have no further right to extend or
renew the Lease Term.

       ii)    The Base Rent payable during the Renewal Term shall be at the
then current Market Rent as of the commencement of such Renewal Term. As used
herein, "Market Rent" shall be the Base Rent for space of equivalent quality,
size, utility and location, with the length of the Renewal Term and
credit-standing of Tenant as well as the amount of Tenant concessions being
offered for comparable first-class office buildings in the Tyson's Corner area
and the operating cost reimbursements and escalations to be taken into account.
If Landlord and Tenant do not agree on the then current Market Rent for the
Renewal Term within thirty (30) days following Landlord's receipt of Tenant's
notice of its intent to exercise its option to renew, the Market Rent shall be
determined as follows:

       The Market Rent shall be determined by a group of three (3) real estate
       brokers, one of whom shall be named by Landlord, one by Tenant, and the
       two so appointed shall select a third. Said brokers shall each be
       licensed in Virginia as real estate brokers specializing in the field of
       commercial leasing, having at least five (5) years' experience, and
       recognized as ethical and reputable within their field. Landlord and
       Tenant agree to make their appointments promptly within ten (10) days
       following the expiration of the aforementioned thirty (30) day period.
       The two brokers selected by Landlord and Tenant shall promptly select a
       third broker. If the two brokers are unable to agree upon a third broker
       within five (5) days after they have both accepted their appointment,
       the parties shall ask the Northern Virginia Association of Realtors to
       appoint such third broker. Within five (5) days after the third broker
       is selected, they shall submit their determination of the Market Rent.
       The Market Rent shall be the mean of the two closest determinations and
       shall be binding on Landlord and Tenant. Landlord and Tenant shall pay
       the costs and expenses of the broker selected by each of them and shall
       share equally the costs and expenses of the third broker.

       iii)   All references in this Lease to the Lease Term shall be construed
to mean both the initial Lease Term and the Renewal Term, if Tenant has
exercised its option and the Renewal Term commences, unless the content clearly
indicates that another meaning is intended.

       iv)    The renewal option may not be exercised by Tenant, if at the time
specified for exercising such option and/or at the date such Renewal Term is to

                                       5
<PAGE>   6
begin, (i) this Lease shall not be in full force and effect, (ii) Tenant shall
not be in actual possession of the entire Premises, or (iii) an Event of
Default shall have occurred and remain uncured under this Lease. If Tenant
shall not be entitled to exercise such option to renew because of the foregoing
provisions of this subsection, such option shall be rendered void and of no
force and effect. It is understood that this renewal option is personal to
Tenant and will not benefit any subtenant of the Premises or any assignee of
this Lease whether or not Landlord has approved such sublease or assignment.

       4.     BASE RENT.

       Tenant shall pay to Landlord at Landlord's address provided herein (or
such other address as may be designated by Landlord in writing from time to
time) the Base Rent for the Premises, without setoff, deduction or demand. The
Base Rent shall be payable on the Phase I Commencement Date and thereafter
monthly, in advance, on the first day of each and every month during the Lease
Term. Base Rent for any portion of a month shall be prorated at the rate of
one-thirtieth (1/30th) of the Base Rent for each day. Landlord shall abate
twenty (20) days of the Base Rent due on the Phase I Space.

       5.     INCREASES IN OPERATING EXPENSES.

       (a)    Commencing on January 1, 1999, Tenant shall pay to Landlord its
proportionate share of the amount by which the Operating Expenses (as
hereinafter defined) incurred by Landlord in the operation of the Complex during
each calendar year exceed the actual Operating Expenses for the Base Year,
calculated as the amount of such increase per square foot of Net Rentable Area
in the Complex. Operating Expenses shall be grossed up to reflect an occupancy
level of ninety-five percent (95%) within the Complex. Since a portion of the
Complex is dedicated to retail uses which do not require many of the services
provided to the office tenants, adjustments in the per-square-foot calculation
of the Operating Expenses shall be made to allocate office Operating Expenses
among the office tenants in the Complex and the other Operating Expenses
chargeable to office and retail tenants among all tenants in the Complex. The
allocation of office Operating Expenses shall be adjusted appropriately in the
event of changes in either the amount of total Net Rentable Area in the Complex
or the amount of office or retail area in the Complex.

       (b)    Operating Expenses are the sum of the following costs and expenses
which in each instance shall be reasonable in amount and of a nature normally
incurred by owners or managers of comparable first-class office buildings in
the Tyson's Corner, Virginia area: (i) Real Estate Taxes (as hereinafter
defined); (ii) gas, water, sewer, electricity and other utility charges
(including surcharges) of every type and nature; (iii) insurance; (iv)
personnel costs, including,

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but not limited to salaries, wages, fringe benefits and other direct and
indirect costs of engineers, superintendents, porters, and other building
personnel not above the level of building manager; (v) costs of all materials,
supplies, labor and other services purchased or levied in connection with the
Complex, including but not limited to, service and maintenance contracts for
chillers, boilers, controls, elevators, windows, janitorial and general
cleaning, and security services; (vi) all other maintenance, repair,
replacement expenses and supplies which are deducted by Landlord in computing
its federal income tax liability; (vii) costs of landscaping, gardening and
planting, cleaning, painting (including striping of parking areas), decorating,
lighting, sanitary control, removal of trash, garbage and other refuse; (viii)
lighting, heating, ventilating and air conditioning of the Complex; (ix) fire
protection; (x) compliance with governmental laws, statutes, regulations and
orders; (xi) management fees; (xii) installing and renting of signs; (xiii)
amortization of capital expenditures made by Landlord during the Lease Term to
reduce Operating Expenses (but only to the extent Operating Expenses are
actually reduced) or to comply with governmental laws, statutes, regulations
and orders; (xiv) any other costs and expenses incurred by Landlord in the
operation of the Complex; and (xv) the costs of any additional services not
provided to the Complex at the Commencement Date but thereafter provided by
Landlord in the prudent management or operation of the Complex. Notwithstanding
anything to the contrary in this Lease, Operating Expenses shall not include
(i) principal or interest payments on any mortgages or deeds of trust; (ii)
depreciation of capital improvements; (iii) amortization of capital
improvements, except as provided above; (iv) the costs of special services,
utilities, and tenant improvement allowances separately chargeable to
individual tenants of the Complex whether or not such costs are reimbursed to
Landlord; (v) expenses associated with leasing space in the Complex or the sale
of any interest in the Complex, including, without limitation, advertising and
marketing, commissions and amounts paid for or on behalf of an individual
tenant such as space planning, moving costs, and rent, improvement and other
concessions; (vi) original construction costs of the Complex; (vii) the costs
of any repair or replacement by reason of a casualty, condemnation, or warranty
claim to the extent Landlord is reimbursed by insurance, condemnation, or
warranty proceeds; (viii) any amount paid to an affiliate (i.e., an entity that
is subject to "control" by the same entity or entities as Landlord), parent or
subsidiary of Landlord, unless the amount paid is a standard "arms length"
price for the type of service rendered; (ix) compensation paid to officers or
executives of Landlord or its management agent other than the management fee;
(x) costs, fines, interest, penalties, legal fees, or other expenses incurred
due to Landlord's violation of any rule or law or the late payment of taxes,
utility bills or other obligations; (xi) Landlord's general corporate overhead
and general administrative expenses; (xii) ground rents; (xiii) costs of
selling, syndicating, financing, mortgaging, or hypothecating any part of or
interest in the Complex; (xiv) reserves for repairs, maintenance and
replacements; or (xv) costs of services provided solely to retail tenants in
the Complex (whether or not such costs are reimbursed to Landlord). In the
event engineers or other personnel delivering services to the Complex are also
assigned to other buildings, the Operating Expenses attributable to their
services shall be based on the reasonable allocation of their services to the
Complex. Management fees shall not exceed the rate customarily charged by
management companies for comparable first-class office buildings in the Tyson's
Corner area. In addition, the rent for space in the Complex used by Landlord's
management company shall

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<PAGE>   8
not exceed the fair market value of such space, and no more than 1,600 square
feet of Net Rentable Area of such space shall be included in Operating Expenses.

       (c)    Real Estate Taxes shall mean (i) all real estate taxes, including
general and special assessments, if any, which are imposed upon Landlord or
assessed against the Complex and (ii) any other present or future taxes or
governmental charges that are imposed upon Landlord or assessed against the
Complex or the equipment, fixtures, or other property therein which taxes or
charges are in the nature of, in addition to, or in substitution for real
estate taxes, including, without limitation, any license fees, business
improvement district fees of any quasi-governmental organization, tax measured
by or imposed upon rents, or other tax or charge upon Landlord's business of
leasing the Complex, but shall not include any federal, state or local income
tax. Real Estate Taxes shall also include all expenses incurred by Landlord in
obtaining or attempting to obtain a reduction of Real Estate Taxes, including,
but not limited to, legal fees.

       (d)    For each calendar year during the Lease Term, Landlord shall
submit to Tenant a statement setting forth Landlord's reasonable estimate of
the amount Tenant will be obligated to pay pursuant to this Section for the
calendar year in question, which reasonable estimate may be revised from time
to time. Tenant shall pay to Landlord on the first day of each month following
receipt of such statement during such calendar year an amount equal to such
estimated amount multiplied by a fraction, the numerator of which is 1, and the
denominator of which is the number of months during such calendar year which
fall within the Lease Term and follow the date of the foregoing statement.
Within ninety (90) days after the expiration of such calendar year, Landlord
shall submit to Tenant a statement showing Tenant's proportionate share of the
increase in the Operating Expenses incurred during such calendar year and the
aggregate amount of the estimated payments made by Tenant on account thereof.
If the aggregate amount of such estimated payments exceeds Tenant's actual
liability for such increase, Tenant shall deduct the net overpayment from its
next monthly payment of Base Rent and additional rent on account of estimated
future increases in the Operating Expenses. If Tenant's actual liability for
such increase exceeds the estimated payments made by Tenant on account thereof,
then Tenant shall immediately pay to Landlord the total amount of such
deficiency.

       (e)    In the event the Lease Term commences or expires during a
calendar year, the increase in the Operating Expenses to be paid by Tenant for
such calendar year shall be determined by multiplying the amount of Tenant's
proportionate share thereof for the full calendar year by a fraction, the
numerator of which is the number of days during such calendar year falling
within the Lease Term, and the denominator of which is 365. Tenant's liability
for its proportionate share of the increase in the Operating Expenses for the
last calendar year falling entirely or partly within the Lease Term shall
survive the expiration of the Lease Term and shall be payable as provided in
this Section.

       (f)    Provided no Event of Default has occurred and is continuing,
Tenant shall have the right, at Tenant's expense, to audit Landlord's books and
records of the Operating Expenses relating to any calendar year for which
payments of increase in Operating Expenses are due from Tenant as additional
rent. No subtenant shall have any right to conduct an audit, and no

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<PAGE>   9
assignee shall conduct an audit for any period during which such assignee was
not in possession of the Premises. Tenant shall provide written notice for such
audit within thirty (30) days following the date that Landlord or its agent
shall have delivered to Tenant the statement of Operating Expenses with respect
to which Tenant desires to make such audit. Such audit shall cover only the
immediately preceding calendar year for the statement being audited and shall be
conducted by an independent certified public accountant at the offices of
Landlord's managing agent or accountant during normal business hours at a time
mutually convenient to Landlord and Tenant. If Landlord's managing agent or
accountant does not have offices in the Washington, D.C. metropolitan area, the
books and records will be made available to Tenant at a mutually agreed location
in such local area. If the audit for such calendar year reasonably suggests
errors in the preceding calendar year, Landlord shall provide the books and
records for more than a total of the three (3) calendar years immediately
preceding the calendar year in which the audit request is made. In no event
shall the accountant be compensated on the basis of a contingent fee
arrangement. Landlord may require as condition of permitting such audit that
Tenant, its principals, employees, and accountants enter into a confidentiality
agreement reasonably acceptable to Landlord. Such audit shall be conducted in
accordance with generally accepted auditing standards of the AICPA. Tenant shall
deliver to Landlord a copy of the results of such audit within five (5) days of
its receipt by Tenant. If Tenant's audit reveals that Landlord's calculation of
additional rent is in error, the corrected amount shall be paid by Tenant to
Landlord within ten (10) days after the completion of the audit, or if Tenant
has already paid the additional rent, the overpayment will be promptly refunded
to Tenant or credited to the next payment of rent due under this Lease.
Notwithstanding anything to the contrary in this Section, in the event that any
such audit reveals that Landlord's calculation of Operating Expenses was
inaccurate by three percent (3%) or more per calendar year, Landlord, not
Tenant, shall pay for the reasonable audit expenses incurred by Tenant up to
Seven Thousand and no/100 Dollars ($7,000.00) provided Tenant presents to
Landlord detailed statements and paid receipts for such services. Landlord shall
pay said expenses within thirty (30) days of Landlord's receipt of the
documentation required under this subsection (f).

       6.     ADDITIONAL RENT/LATE FEES. All payments required to be made by
Tenant pursuant to this Lease shall be deemed rent for the Premises, whether or
not expressly characterized as rent, the nonpayment of which shall entitle
Landlord to exercise all such rights and remedies as are herein provided in the
case of the nonpayment of Base Rent. Notwithstanding any dispute which may arise
in connection with the computation or estimate of any amount due under this
Lease, Tenant shall be obligated to pay the amount specified by Landlord without
set-off or deduction pending the resolution of any dispute. The agreements of
Tenant to pay Base Rent, increases in Operating Expenses, and other charges
pursuant to this Lease constitute covenants of Tenant, which covenants are
independent of all other covenants or obligations of either party hereunder, and
Tenant hereby irrevocably waives any claim or defense of offset, deduction,
withholding, and waives any notice or demand in excess of notices otherwise
provided in this Lease, with respect to the performance (or default in
performance) of Tenant's covenants to pay Base Rent and such other charges. In
the event any installment of rent is not paid within five (5) days of the date
when due and payable (regardless of any

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<PAGE>   10
notice period provided in Section 26(a)(i) of this Lease), Tenant shall pay a
late charge of four percent (4%) of the delinquent amount.

       7.     USE. Tenant shall use and occupy the Premises solely for general
office purposes and incidental purposes specifically related to the computer and
telecommunications business conducted by Tenant provided such uses do not
violate Section 17 of this Lease and for no other use or purpose without the
prior written consent of Landlord. Tenant represents and warrants that it is
not, and will not operate the Premises as, a place of public accommodation for
the purposes of the Americans with Disabilities Act (the "ADA"), as it may be
amended from time to time. Tenant shall not use or occupy the Premises for any
unlawful purpose or in any manner that will constitute waste, nuisance or
unreasonable annoyance to Landlord or other tenants of the Complex or for any
purpose prohibited in the rules and regulations promulgated by Landlord. Tenant
acknowledges that a use which attracts a large number of people, such as an
employment agency or public defender's office, would cause unreasonable
annoyance to Landlord. If any present or future law, ordinance, regulation or
order requires an occupancy permit for the Premises, Tenant will obtain such
permit at Tenant's own expense.

       8.     SERVICES TO BE FURNISHED BY LANDLORD.

       (a)    Landlord agrees to furnish Tenant the following services:

              i)     Hot and cold water at those points of supply provided for
       general use of other tenants in the Complex and any pantry included
       within the Premises, central heat and air conditioning in season, at such
       temperatures and in such amounts as are considered by Landlord to be
       standard or as required by governmental authority; provided, however,
       heating and air conditioning service at times other than for Normal
       Business House (as hereinafter defined) shall be furnished only upon
       Tenant's written request to Landlord prior to 3:00 p.m. at least one (1)
       business day in advance of the date such usage is requested. As used
       herein, Normal Business Hours shall be 7:30 a.m. to 6:00 p.m. on Mondays
       through Fridays and 8:00 a.m. to 1:00 p.m. on Saturdays, exclusive of
       Normal Business Holidays (as hereinafter defined). As used herein, Normal
       Business Holidays shall include Sundays and all legal holidays specified
       in the rules and regulations for the Complex. Tenant shall bear the
       entire cost of additional service allocable to the Premises as such costs
       are determined and allocated by Landlord from time to time.

              ii)    Routine maintenance and electrical lighting service for
       all Exterior Common Areas and Service Areas in the manner and to the
       extent deemed by Landlord to be standard.

              iii)   Janitor service, Mondays through Fridays, exclusive of
       Normal Business Holidays; provided, however, if Tenant's floor covering
       or other improvements require special treatment, Tenant shall pay the
       additional cleaning

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<PAGE>   11
cost attribute thereto as additional rent upon presentation of a statement
therefor by Landlord. Tenant shall cooperate with Landlord's employees in the
furnishing by Landlord of janitorial services at such times (including Normal
Business Hours) as Landlord elects to have the necessary work performed;
provided, however, that janitorial services performed by Landlord during Normal
Business Hours shall be performed in such a manner as to not unreasonably
interfere with Tenant's use of the Premises.

              iv)    Subject to the provisions of the Section captioned "Use of
       Electrical Services by Tenant", facilities to provide all electrical
       current required by Tenant in its use and occupancy of the Premises.

              v)     All standard fluorescent bulb replacement in the Premises
       and fluorescent and incandescent bulb replacement in the Common Areas and
       Service Areas.

              vi)    Landlord shall provide card key access to the Complex
       during periods other than Normal Business Hours, and Tenant shall
       cooperate with Landlord in limiting the use of card keys to persons
       authorized by Tenant to enter the Complex. Landlord, however, shall have
       no liability to Tenant, its employees, agents, invitees or licensees for
       losses due to theft or burglary, or for damages done by unauthorized
       persons on the Premises, nor shall Landlord be required to insure against
       any such losses. Tenant shall cooperate fully in Landlord's efforts to
       maintain security in the Complex and shall follow all rules and
       regulations promulgated by Landlord with respect thereto.

       b)     The failure by Landlord to any extent to furnish or the
interruption or termination of these defined services in whole or in part,
resulting from causes beyond the reasonable control of Landlord shall not
render Landlord liable in any respect nor be construed as an eviction of
Tenant, nor work an abatement of rent, nor relieve Tenant from the obligation
to fulfill any covenant or agreement hereof. Should any of the equipment or
machinery used in the provision of such services for any cause cease to
function properly, Tenant shall have no claim for offset or abatement of rent
or damages on account of interruption in service occasioned thereby or
resulting therefrom. Notwithstanding the foregoing, in the event there shall be
an interruption or cessation of the building's elevator service, electricity
service, or HVAC service in the manner required to be provided by Landlord
under this Lease, which shall materially interfere with Tenant's use and
enjoyment of all or substantially all of the Premises (a "Service
Interruption"), and (i) if such Service Interruption shall continue for at
least ten (10) consecutive business days following receipt by Landlord of
written notice from Tenant describing such Service Interruption (the "Service
Interruption Notice"), (ii) if such Service Interruption shall not have been
caused, in whole or in part, by any act, omission or negligence of Tenant or of
Tenant's agents, employees, contractors or visitors, and (iii) if such Service
Interruption shall not have been caused in whole or in part by a fire or other
casualty or an event of force majeure as described in Section 42(j) of this
Lease (a Service Interruption that satisfies all of the

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<PAGE>   12
foregoing conditions being referred to hereinafter as a "Material Service
Interruption"), then as Tenant's sole and exclusive remedy in connection with
such Material Service Interruption, Landlord shall abate the Base Rent and all
additional rent in the same proportion as the portion of the Premises affected
by the Material Service Interruption bears to the entire Premises for the period
which shall begin on the commencement of such Material Service Interruption and
which shall end on the day such Material Service Interruption shall cease.
Landlord, however, shall have no obligation to provide such an abatement if
Tenant's personnel are occupying the Premises or the affected portion thereof
during the period of the Material Service Interruption.

       9.     IMPROVEMENTS.

       (a)    Tenant has inspected the Premises and accepts the Premises "as
is". Landlord will not make, and is under no obligation to make, any structural
or other alterations, decorations, additions or improvements in or to the
Premises except as set forth in Exhibit B or as otherwise provided in this
Lease. All installations and improvements now or hereafter placed on the
Premises shall be for Tenant's account and at Tenant's cost (and Tenant shall
pay ad valorem taxes and increased insurance thereon or attributable thereto),
which cost shall be payable by Tenant to Landlord in advance as additional rent.

       (b)    Tenant will not make or permit anyone to make any alterations,
decorations, additions or improvements, structural or otherwise, in or to the
Premises or the Complex, without the prior written consent of Landlord, which
consent shall not be unreasonably withheld or delayed. When granting its
consent, Landlord may impose any reasonable conditions it deems appropriate,
including, without limitation, the approval of plans and specifications,
approval of the contractor or other persons to perform the work, and the
obtaining of specified insurance. All improvements permitted by Landlord must be
performed by bonded contractors and must conform to all rules and regulations
established from time to time by the Board of Fire Underwriters having
jurisdiction or similar body exercising similar functions and to all laws,
regulations and requirements of the federal, Virginia and Fairfax County
governments. Tenant shall obtain and deliver to Landlord written unconditional
waivers or releases of mechanic's and materialmen's liens against the Complex
and the land upon which it is situated from all contractors, subcontractors,
architects, engineers, laborers and material suppliers for all work, labor and
services performed and material furnished in connection with improvements to the
Premises. Any alterations, decorations, additions or improvements to the
Premises, other than those made by Landlord pursuant to Exhibit B, shall be
conducted on behalf of Tenant and not on behalf of Landlord, and Tenant shall
not be deemed to be the agent of Landlord. In the event Landlord shall give its
written consent to the making of any improvements to the Premises, such written
consent shall not be deemed to be an agreement or consent by Landlord to subject
its interest in the Premises, the Complex, or the land upon which it is situated
to any mechanic's or materialmen's liens which may be filed in connection
therewith. Tenant shall supply Landlord with as-built plans showing all
improvements by Tenant to the Premises or the Complex promptly upon completion
of each such improvement. Except as otherwise expressly provided in this Lease,
Landlord shall not be required to make any repairs to the Premises.

                                       12
<PAGE>   13

      10.    MECHANIC'S LIENS. Tenant will not suffer or permit any mechanic's
lien or liens to be placed upon the Premises or the Complex arising out of any
work contracted for or authorized by Tenant in respect to the Premises. Nothing
in this Lease shall be deemed or construed in any way as constituting the
consent or request of Landlord, express or implied, by inference or otherwise,
to any person for the performance of any labor or the furnishing of any
materials to the Premises, or any part thereof, nor as giving Tenant any right,
power, or authority to contract for or permit the rendering of any services or
the furnishing of any materials that would give rise to any mechanics' or other
liens against the Premises. In the event any such lien is attached to the
Complex or Tenant's interest in the Premises, Tenant shall immediately cause
same to be released or bonded off, and if Tenant fails to do so, then, in
addition to any other right or remedy of Landlord, Landlord may, but shall not
be obligated to, discharge the same. Any costs and expenses incurred by
Landlord for any of the aforesaid purposes shall be paid by Tenant to Landlord
on demand as additional rent.

      11.    CARE OF THE PREMISES BY TENANT. Tenant agrees not to commit or
allow any waste to be committed on any portion of the Premises and at the
termination of this Lease to deliver up the Premises to Landlord in as good
condition as at the date of the commencement of the Lease Term, ordinary wear
and tear and insured casualty losses excepted. Tenant shall not install any
equipment of any type or nature that will or may necessitate any changes,
replacements or additions to, or in the use of, the water system, heating
system, plumbing system, air-conditioning system or electrical system of the
Premises or the Complex, without first obtaining the prior written consent of
the Landlord. Business machines and mechanical equipment belonging to Tenant
which cause noise or vibration that may be transmitted to the structure of the
Complex or to any space therein to such a degree as to be objectionable to
Landlord or to any tenant in the Complex shall be installed and maintained by
Tenant, at Tenant's expense, on vibration eliminators or other devices
sufficient to reduce such noise and vibration to a level satisfactory to
Landlord.

      12.    REPAIRS BY TENANT. Tenant covenants and agrees with Landlord, at
Tenant's own cost and expense, to repair or replace any damage done to the
Premises or the Complex, or any part thereof, caused by Tenant or Tenant's
agents, employees, or invitees. Such repairs shall restore the Premises or the
Complex to the condition existing prior to such damage and shall be effected in
compliance with all applicable laws; provided, however, if Tenant fails to make
such repairs or replacements promptly, Landlord may, at its option, make
repairs or replacements, and Tenant shall pay the cost thereof to Landlord on
demand as additional rent. All improvements to the Premises or the Complex made
by either party shall immediately become the property of Landlord and shall
remain upon and be surrendered with the Premises as a part thereof at the end
of the Lease Term. Notwithstanding the foregoing, (i) if Tenant is not in
default under this Lease, Tenant shall have the right to remove, prior to the
expiration of the Lease Term, all movable furniture, furnishings and equipment
installed in the Premises solely at the expense of Tenant and (ii) Landlord
shall have the right to require Tenant, at the end of the Lease Term, to
remove all tenant improvements and fixtures installed by Tenant in the Phase I
Space and the Phase II Space after the Phase I Commencement Date and the Phase
II Commencement, respectively, at the sole cost of Tenant. Notwithstanding
the foregoing, if

                                       13

<PAGE>   14

Tenant so requests, Landlord will state in writing at the time of Landlord's
approval of Tenant's proposed improvements to the Premises, which improvements
Landlord will not require Tenant to remove at the expiration or earlier
termination of this Lease. In the event that Landlord elects to require Tenant
to remove improvements installed by Tenant, and Tenant fails to remove such
improvements, Landlord may remove them at Tenant's cost, and Tenant shall pay
Landlord on demand the cost of restoring the Premises to their condition prior
to the installation of such improvements.

      13.    SIGNAGE AND WINDOW TREATMENTS.

      (a)    No sign, advertisement or notice referring to Tenant shall be
inscribed, painted, affixed or otherwise displayed on any part of the exterior
or the interior of the Complex except on the directories and the doors of
offices and such other areas as are designated by Landlord, and then only in
such place, number, size, color and style as are approved by Landlord. All of
Tenant's signs that are approved by Landlord shall be installed by Landlord at
Tenant's cost and expense. Tenant shall reimburse Landlord for such amount upon
written demand from Landlord and such sum shall be considered additional rent
hereunder. The color and fabric of the lining of all drapes (or if unlined, the
draperies themselves) which Tenant desires to place on exterior windows or
openings of the Building must be approved by Landlord prior to the installation
thereof so that a uniform color and appearance may be preserved from the
exterior of the Complex. Landlord agrees to furnish a directory of the names
and locations of its tenants and to install and maintain the same at a
convenient location in the lobby of each building in the Complex. The initial
listing of the name and room number of Tenant shall be furnished without
charge. The listings of additional names or room numbers and changes or
revisions of listings shall be made by Landlord at the cost of Tenant. If any
sign, advertisement or notice that has not been approved by Landlord is
exhibited or installed by Tenant, Landlord shall have the right to remove the
same at Tenant's expense. Landlord reserves the right to affix, install and
display signs, advertisements and notices on any part of the exterior or
interior of the Complex except the Premises.

      (b)    Subject to the rights of Rafie and Associates/The Guardian
("Rafie"), a tenant in the Building, Tenant shall have the nonexclusive right
to install an exterior sign on the top spandrel of the Building provided (i)
Tenant expands the Premises in the Building to a size larger than 20,914 square
feet of Net Rentable Area and (ii) Tenant is leasing and is actually occupying
the largest amount of Net Rentable Area in the Building. For purposes of this
subsection (b), in determining the amount of square feet of Net Rentable Area
leased by Tenant in the Building, no portion of the Premises subject to an
assignment or sublet will be included. The location and specification of said
sign or any changes thereto after the sign is installed are subject to
Landlord's prior written consent, it being understood that Landlord may
withhold its consent if in Landlord's judgment, such sign is aesthetically
inconsistent with the character of the Complex. The sign must be no longer than
one hundred fifteen (115) feet with letters not exceeding four (4) feet in
height. If at any time Tenant no longer satisfies the criteria in subsections
(i) and (ii) above, Landlord may require Tenant to remove the exterior sign at
Tenant's sole cost and expense. Any sign installed pursuant to this subsection
(b) shall be installed and maintained and,

                                       14
<PAGE>   15

upon the expiration or earlier termination of this Lease, shall be removed, at
Tenant's sole cost and expense. Upon the removal of the sign, Tenant shall
restore the Building to the condition that existed prior to the installation of
the sign. The sign shall comply with all applicable laws and ordinances, and
any permits therefor shall be obtained by Tenant at Tenant's expense.

      (c)    In the event Landlord offers any tenant (other than Rafie)
occupying a single floor or less in the Building the right to install an
exterior sign on the top spandrel of the Building, Landlord shall first give
Tenant written notice of such offer, and if Tenant does not then satisfy
criteria (i) and (ii) in subsection (b) above and has not assigned or sublet
any portion of the Premises, Tenant shall have the prior right to install such a
sign provided Tenant gives Landlord written notice no later than five (5)
business days after Tenant's receipt of Landlord's notice. If Tenant does not
install its sign within one hundred twenty (120) days after exercising its
right to do so, Landlord may offer the exterior signage right to any other
tenants in the Building and Tenant's rights under this subsection (c) shall be
of no further force and effect. Landlord will provide good faith responses to
Tenant's requests regarding the rights of other tenants occupying a single
floor or less to install a sign on the spandrel.

      14.    USE OF ELECTRICAL SERVICES BY TENANT. Tenant's use of electrical
services furnished by Landlord shall be subject to the following:

             i)     Tenant's electrical equipment shall be restricted to that
      equipment which individually does not have a rated capacity greater than
      .5 kilowatts per hour and/or require voltage other than 120/208 volts,
      single phase. Collectively, Tenant's equipment shall not have an
      electrical design load greater than an average of 2 watts per square
      foot.

             ii)    Tenant's lighting shall not have a design load greater than
      an average of 2 watts per square foot.

             iii)   Landlord shall be entitled to enter the Premises to perform
      an audit or survey of electrical use thereon from time to time. Tenant's
      consumption of electrical services shall not exceed either the rated
      capacities and/or design loads set forth in subsections (i) and (ii)
      above nor shall it generate heat in excess of that which Landlord's air
      conditioning system is designed to handle. In the event that Tenant
      elects to add equipment and/or lighting to the Premises that will cause
      Tenant's consumption of electrical services to exceed either the rated
      capacities and/or design loads set forth in subsections (i) and (ii)
      above or that will generate heat in excess of that which Landlord's air
      conditioning system is designed to handle, Tenant shall obtain Landlord's
      prior written approval of such equipment and/or lighting subject to the
      following:

                    (1)    Tenant shall pay for all costs of installation and
             maintenance of submeters, wiring, additional air conditioning
             systems and other items required by Landlord, in Landlord's

                                       15

<PAGE>   16

             discretion, to accommodate Tenant's excess design loads and
             capacities or heat production.

                    (2)    Tenant shall pay to Landlord, upon demand, the cost
             of the excess demand and consumption of electrical service at
             rates determined by Landlord (which rates shall be in accordance
             with any applicable laws) as well as all costs of operating
             additional air conditioning systems deemed necessary by Landlord
             on account of Tenant's excess consumption.

                    (3)    Landlord may, at its option, upon not less than
             thirty (30) days' prior written notice to Tenant, discontinue the
             availability of any or all utility service and in such event
             Tenant shall contract directly with such public utility for the
             supplying of such additional utility service to the Premises.

Landlord hereby approves the loads designed in the Space Plan and Construction
Specifications attached as Exhibit B-1 to the Work Agreement and confirms that
no additional costs will be incurred to provide such capacity.

      15.    PARKING.

      (a)    Tenant shall have  the right to use sixty-three (63) parking
spaces (i.e., three spaces for each 1,000 square feet of Net Rentable Area
leased) in the garage of the Complex throughout the Lease Term at no charge.
All parking spaces will be unreserved except for one, which will be a reserved
space reasonably close to the elevator core of the Building. However, until the
Phase II Commencement Date, Tenant shall have the right to use only forty (40)
of said sixty-three (63) parking spaces. Landlord may, in its sole and absolute
discretion, designate parking areas within the Complex for Tenant and Tenant's
agents and employees. In the event that Tenant, its agents and employees park
in locations other than those assigned to Tenant, Landlord reserves the right
to charge Tenant a fee of Twenty-Five and no/100 Dollars ($25.00) per day,
which fee is subject to increase from time to time at Landlord's sole option,
for each such occurrence in addition to towing such cars at Tenant's expense.
Cars not parked according to the rules and regulations promulgated by Landlord
may be towed at the owner's expense.

      (b)    Use of the parking facilities serving the Complex is at the sole
risk of the users of such facilities, and Landlord assumes no liability for
personal injury, theft or property damage, or any other loss occurring during,
as a result of, or in connection with such use. Landlord shall have no
liability whatsoever to Tenant or any other person (including, without
limitation, Tenant's agents, employees, invitees, guests, clients, or
customers) for any property damage to vehicles or their contents and/or personal
injury which might occur as a result of or in connection with the parking of
vehicles in or about the Complex. Tenant shall indemnify and hold Landlord
harmless from and against any and all costs, claims, causes of action, and
expenses (including reasonable attorneys' fees) which Landlord may incur in
connection with

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<PAGE>   17
condition of the Premises and all machinery, equipment and furnishings therein.
Tenant shall pay all costs, expenses, liabilities, losses, damages, fines,
penalties, claims and demands, including reasonable attorneys' fees, that may in
any manner arise out of or be imposed because of the failure of Tenant to comply
with the covenants of this Section. Landlord represents and warrants that the
tenant improvements to be constructed by Landlord pursuant to Exhibit B attached
hereto will comply with the ADA and all other applicable laws, ordinances,
regulations, and orders as of the date Landlord delivers possession of the Phase
I Space and the Phase II Space to Tenant. Landlord shall comply with such laws,
ordinances, regulations and orders concerning (i) the use, occupancy and
condition of the Common Areas and Exterior Common Areas of the Complex, (ii) the
condition and maintenance of the structure of the Complex and (iii) the
operation, maintenance, and repair of the mechanical, electrical, and plumbing
systems (including, without limitation, the HVAC and life safety systems)
serving the entire Complex. It is expressly understood that if any present or
future law, ordinance, regulation or order requires an occupancy permit for the
Premises, Tenant will obtain such permit at Tenant's own expense; however, the
nonresidential use permit(s) to be obtained in connection with the improvements
constructed by Landlord pursuant to the Work Agreement attached hereto as
Exhibit B shall be obtained by Landlord at Landlord's expense.

          18. ENTRY BY LANDLORD. Upon reasonable oral notice to Tenant, Tenant
shall permit Landlord or its agents or representatives to enter into and upon
any part of the Premises at all-reasonable hours (and in emergencies at all
times) to inspect the same, or to show the Premises to prospective purchasers,
mortgagees, tenants, or insurers, to clean or make repairs, alterations or
additions thereto, and Tenant shall not be entitled to any abatement or
reduction of rent by reason thereof. Tenant agrees to cooperate with Landlord in
event of emergencies, including, without limitation, evacuation at Landlord's
oral request in the event of any situation deemed by Landlord as an emergency.

          19. ASSIGNMENT AND SUBLETTING.
              -------------------------

          (a) Tenant shall not assign, transfer, mortgage or otherwise encumber
this Lease or its interest therein, or sublet, rent or permit anyone to occupy
the Premises, or any part thereof, without giving Landlord fifteen (15) business
days' prior written notice of Tenant's intention to assign or sublet the
Premises and obtaining the prior written consent of Landlord. Landlord shall not
withhold or delay its consent to any assignment of this Lease or a sublease of
the Premises if all of the following conditions have been satisfied: (i) Tenant
shall have demonstrated, to Landlord's satisfaction, that the use of the
Premises shall comply with the terms of this Lease and that, in the case of an
assignment, the credit-worthiness of the assignee is comparable to that of other
tenants in the Complex for similar leases in space of similar size or quality;
(ii) the form and content of any assignment or sublease documents shall have
been reasonably approved by Landlord and its counsel; (iii) Tenant shall have
reimbursed Landlord for any reasonable attorneys' fees and expenses incurred by
Landlord in connection with such assignment or sublease; and (iv) the assignee
or subtenant is not a tenant in the Complex unless Landlord confirms that there
is no prime office space available. Notwithstanding anything to the contrary in
this Lease, Landlord may condition its consent to a proposed assignment upon

                                       18

<PAGE>   18

Tenant's execution and delivery of a guaranty in a form acceptable to Landlord
and its counsel of the monetary performance by the proposed assignee of its
financial obligations under this Lease. If Landlord denies consent to an
assignment solely because of the credit-worthiness of the assignee and there has
been no deterioration in the credit-worthiness of Tenant since the date of this
Lease, Tenant may satisfy such condition by posting a security deposit and/or
providing a lease guaranty acceptable to Landlord. No assignment or transfer of
this Lease or the right of occupancy hereunder may be effectuated by operation
of law or otherwise without the prior written consent of Landlord. The consent
by Landlord to any assignment or subletting shall not be construed as a waiver
or release of Tenant from liability for the performance of all covenants and
obligations to be performed by Tenant under this Lease, nor shall the collection
or acceptance of rent from any assignee, subtenant or occupant constitute a
waiver or release of Tenant from any of its liabilities or obligations under
this Lease. Landlord's consent to any assignment or subletting shall not be
construed as relieving Tenant from the obligation of obtaining Landlord's prior
written consent to any subsequent assignment or subletting. If an Event of
Default has occurred and is continuing, Tenant hereby assigns to Landlord the
rent due from any subtenant of Tenant and hereby authorizes each such subtenant
to pay said rent directly to Landlord. Tenant shall pay to Landlord a Five
Hundred Dollar ($500.00) processing fee as well as expenses (including
reasonable attorneys' fees) incurred by Landlord in connection with Tenant's
request for Landlord to give its consent to any assignment, subletting,
occupancy or mortgage, whether or not Landlord consents thereto.

          (b) If Tenant is a partnership, a withdrawal or change, whether
voluntary, involuntary or by operation of law, of partners owning a controlling
or majority interest in Tenant shall be deemed a voluntary assignment of this
Lease and subject to the provisions of subsection (a) above. If Tenant is a
corporation, any dissolution, merger, consolidation or other reorganization of
Tenant, or the sale or transfer (whether by way of one or more sales or
transfers) of a controlling or majority interest of the capital stock of Tenant
shall be deemed a voluntary assignment of this Lease and subject to the
provisions of this Section. However, the preceding sentence shall not apply to
corporations the stock of which is traded through a national or regional
exchange or over-the-counter.

          (c) If Tenant desires to assign or sublet more than fifty percent
(50%) of the rentable area of the Premises (i.e., 50% in the aggregate
including any prior or simultaneously assigned or subleased space), Landlord
shall have the option to terminate this Lease with regard to that portion of the
Premises that Tenant desires to assign or sublet and, in addition, Landlord
shall have the option to require any existing assignees or sublessees of Tenant
to attorn to Landlord. Landlord may exercise the option by giving Tenant written
notice within thirty (30) days after Landlord has received Tenant's written
notice of intention to assign or sublet pursuant to this Section. The effective
date of termination shall be mutually agreed upon by Landlord and Tenant, and,
if they cannot agree upon a termination date, the termination date will be
ninety (90) days from the date Landlord received the notice that Tenant desires
to assign or sublet more than fifty percent (50%) of the rentable area of the
Premises. Upon termination, all of the rights and obligations of Landlord and
Tenant under the terms of this Lease shall be terminated with regard only to
that portion of the rentable area of the Premises which Tenant notified Landlord

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<PAGE>   19

that Tenant desires to assign or sublet, except the obligation of Tenant to pay
rent and all other charges that accrue to the date of termination. The options
of Landlord under this Section shall apply to each assignment or sublease by
Tenant and a waiver by Landlord as to one assignment or sublease shall not
affect any subsequent assignment or sublease.

          (d) If Tenant desires to assign or sublet the whole or a part of the
Premises, Landlord may condition its consent to the subletting or assignment on
the requirement that fifty percent (50%) of the net profit derived by Tenant
from the assignment or subletting shall be paid by Tenant to Landlord as
additional rent. Net profit shall be deemed to mean the net proceeds received by
Tenant from any subletting or assignment less brokerage and other expenses
incurred in making the assignment or sublease amortized, however, over the term
of the assignment or sublease, said net profit to be paid monthly to Landlord by
Tenant at the times that the subrent or assignment charge is paid by the
subtenant or assignee to Tenant and as and when the same is received by Tenant.
Tenant expressly waives any right that it may have to retain such excess
pursuant to the provisions of Section 365(f) of the Bankruptcy Code.

          20. INSURANCE.
              ---------

          (a) Throughout the Lease Term, Tenant shall obtain and maintain
commercial general liability insurance on an occurrence basis protecting against
any liability occasioned by any occurrence on or about the Premises and
containing contractual liability coverage. Such insurance shall be initially in
minimum amounts of Two Million Dollars ($2,000,000) per occurrence and shall be
for a minimum term of one (1) year.

          (b) Throughout the Lease Term, Tenant shall also obtain and maintain
throughout the Lease Term insurance coverage for all risks and perils as
customarily provided by insurance companies to insure against damage to or loss
of the contents of the Premises, including, without limitation, alterations,
decorations, or improvements to the Premises previously made by Tenant or any
trade fixtures, furnishings, equipment or personal property belonging to Tenant.
Such policy shall be for the full insurable value of such property and shall not
be subject to a deductible in excess of $10,000.

          (c) Each of said policies of insurance shall name Landlord and
Landlord's managing agent as an additional insured, and if requested by the
holder of any mortgage or deed of trust against the Complex, the public
liability policy referred to above shall also name such holder as an additional
insured. Each policy shall contain an endorsement which provides that no
cancellation or reduction of coverage may be made without first giving Landlord
and, if named as an additional insured, the holder of any mortgage or deed of
trust on the Complex, at least thirty (30) days' prior written notice of such
proposed action. All of Tenant's insurance required under this Lease shall be
written as primary policy coverage and not contributing with or in excess of any
coverage which Landlord may carry. All insurance policies required from Tenant
under this Lease shall be issued by insurance companies licensed to do business
in the jurisdiction wherein the Complex is located with a financial rating of at
least an A:XII as rated in the most recent edition of Best Insurance Reports and
in business for the past five (5) years.

                                       20
<PAGE>   20

On or before the Phase I Commencement Date, and thereafter not less than fifteen
(15) days prior to the expiration dates of said policy or policies, Tenant shall
provide copies of policies or certificates of insurance (ACORD 27) evidencing
the coverages required by this Section. The aforesaid insurance limits may be
reasonably increased from time to time by Landlord.

          (d) Throughout the Lease Term, Landlord shall obtain and maintain (i)
insurance against all risks of physical loss or damage to the Complex and (ii)
comprehensive liability insurance on an "occurrence basis" against claims or
damages of death, bodily injury, or property damage occurring in or about the
Complex. All insurance maintained by Landlord shall be in amounts deemed
reasonable and prudent for a first-class office building in the Tyson's Corner
business district.

          (e) Anything in this Lease to the contrary notwithstanding, Landlord
and Tenant each hereby waives any and all rights of recovery, claim, action, or
cause of action, against the other, its agents, officers, or employees, for any
loss or damage that may occur to the Premises, or any improvements thereto, or
the Complex of which the Premises are a part, or any improvements thereto, or
any personal property of such party therein, by reason of fire, the elements, or
any other cause(s) which may be insured against under the terms of insurance
policies properly endorsed, regardless of cause or origin, including negligence
of the other party hereto, its agents, officers, or employees, and without
regard to whether any such policies are maintained, and without regard to the
amount of any deductibles. The provisions of this Section are conditioned upon
the ability of Landlord and Tenant to each obtain endorsements, at no additional
cost, to their property insurance with respect to the Complex consistent with
this Section. Each property insurance policy shall also provide that the policy
shall not be invalidated in the event that the insured waives, in writing prior
to a loss, any or all rights of recovery against any party for losses covered by
such policy. If Tenant is unable to obtain the provisions set forth herein from
its property insurance company, Tenant shall name Landlord as an insured on
Tenant's property insurance policy.

          21. PROPERTY TAXES. Landlord agrees to pay all Real Estate Taxes, and
increases in Real Estate Taxes shall be passed through to Tenant as Operating
Expenses to be paid in accordance with the terms of this Lease. Tenant shall be
liable for all taxes levied against personal property and trade fixtures placed
by Tenant in the Premises. If any taxes for which Tenant is liable under this
Section are levied against Landlord or Landlord's property and if Landlord
elects to pay the same or if the assessed value of the Complex is increased by
inclusion of personal property and trade fixtures placed by Tenant in the
Premises and Landlord elects to pay the taxes based on such increase, Tenant
shall pay to Landlord upon demand as additional rent that part of such taxes for
which Tenant is primarily liable hereunder.

          22. MUTUAL INDEMNIFICATION. Subject to the waiver of claims set forth
in Section 20(e) of this Lease, Tenant shall indemnify and hold Landlord and
Landlord's agents and its and their officers, directors, and employees, harmless
from and against all costs, damages, claims, liabilities and expenses (including
reasonable attorneys' fees) suffered by or claimed against Landlord and
Landlord's agents and its and their officers, directors, and employees, directly
or

                                       21

<PAGE>   21
indirectly, based on, arising out of or resulting from (i) Tenant's use and
occupancy of the Premises or the business conducted by Tenant therein, (ii) any
negligent act or omission by Tenant or its employees, agents or invitees, or
(iii) any breach or default by Tenant in the performance or observance of its
covenants or obligations under this Lease. Subject to the waiver of claims set
forth in Section 20(e) of this Lease, Landlord shall indemnify and hold Tenant
and Tenant's agents and its and their officers, directors and employees harmless
from and against all costs, damages, claims, liabilities and expenses (including
reasonable attorneys' fees) suffered by or claimed against Tenant and Tenant's
agents and its and their officers, directors, members, and employees to the
extent directly or indirectly, based on, arising out of or resulting from (i)
any negligent act or omission by Landlord or its employees, agents or invitees,
in the operation of the Complex; (ii) latent defects in the Complex; or (iii)
any breach or default by Landlord in the performance or observance of its
covenants or obligations under this Lease.

       23.    CASUALTY DAMAGE. If the Premises or any part thereof shall be
damaged by fire or other casualty, Tenant shall give prompt written notice
thereof to Landlord. In case the Complex shall be so damaged that substantial
alteration or reconstruction of the Complex shall, in Landlord's reasonable
opinion, be required (whether or not the Premises shall have been damaged by
such casualty) or in the event any mortgagee of Landlord's should require that
the insurance proceeds payable as a result of a casualty be applied to the
payment of the mortgage debt and not to reconstruction of the Complex, or in the
event of any material uninsured loss to the Complex for which Landlord is not
required to insure under the terms of this Lease, Landlord may, at its option,
terminate this Lease by notifying Tenant in writing of such termination within
ninety (90) days after the date of such damage. In furtherance of the foregoing,
but not in limitation thereof, if the repairs and restoration of the Premises
cannot be completed within one hundred fifty (150) days after the occurrence of
such damage (taking into account the time needed for removal of debris,
preparation of plans and issuance of all required governmental permits),
Landlord and Tenant shall have the right, at the option of either, to terminate
this Lease as described in the following sentences. Within forty-five (45) days
after the occurrence of such damage, Landlord shall provide reasonable
assurances to Tenant that such repairs and restoration can be substantially
completed within one hundred fifty (150) days of the occurrence of the damage
and that Landlord intends to perform such repairs and restoration. If Landlord
so informs Tenant that such repairs and restoration can be completed within such
time, this Lease shall continue and Landlord shall use its reasonable best
efforts to complete said repairs and restoration within said 150-day period. If
Landlord fails to provide such assurances, then Tenant shall have the right to
notify Landlord within fifteen (15) days that it is terminating this Lease. If
the restoration of the Premises is not substantially completed within said
150-day period due to no fault of Tenant, Tenant shall have the right to
terminate this Lease by giving notice to Landlord no later than the second
business day following the end of said 150-day period. If this Lease is
terminated pursuant to the preceding sentences, all rent payable hereunder shall
be apportioned and paid to the date of the occurrence of such damage. If this
Lease is not terminated, Landlord shall, following settlement of Landlord's
insurance claims, promptly commence and proceed with reasonable diligence to
restore the Premises and the Complex to substantially the same condition in
which they were immediately prior to the

                                       22

<PAGE>   22

happening of the casualty, except that Landlord's obligation to restore shall
not exceed the scope of the work required to be done at Landlord's expense in
originally constructing the Complex and the scope of the work in the Premises as
described in the Work Agreement attached hereto as Exhibit B, nor shall Landlord
be required to spend an amount in excess of the deductible amount in Landlord's
policy and the insurance proceeds actually received by Landlord as a result of
the casualty. At such time as Landlord has completed its reconstruction
obligations as above set forth, Tenant shall, at Tenant's expense, complete the
restoration of the Premises. Landlord shall not be liable to Tenant for the
repair or replacement of any installation made by Tenant. Repairs or
replacements of installations made by Tenant or of Tenant's furniture, fixtures,
equipment and contents shall be made by Tenant at its sole cost. Landlord shall
not be liable for any inconvenience or annoyance to Tenant or injury to the
business of Tenant resulting in any way from such damage or the repair thereof,
except that, subject to the provisions of the next sentence, Landlord shall
allow Tenant a pro rata diminution of rent during the time and based on the
portion of the Premises that are damaged and unfit for occupancy. If the
Premises or any other portion of the Complex is damaged by fire or other
casualty resulting from the negligence of Tenant or any of Tenant's agents or
employees, the rent hereunder shall not be diminished during the repair of such
damage.

       24.    CONDEMNATION. If the whole or substantially the whole of the
Complex or the Premises should be taken for any public or quasi-public use, by
right of eminent domain or otherwise or should be sold in lieu of condemnation,
then this Lease shall terminate as of the date when physical possession of the
Complex or the Premises is taken by the condemning authority, and rent shall be
prorated as of such date. If less than the whole or substantially the whole of
the Complex or the Premises is thus taken or sold, Landlord (whether or not the
Premises are affected thereby) may terminate this Lease by giving written notice
thereof to Tenant, in which event this Lease shall terminate as of the date when
physical possession of such portion of the Complex or Premises is taken by the
condemning authority. If as a result of the condemnation, a material portion of
the Premises are taken and are rendered unsuitable for Tenant's business
operations, Tenant may terminate this Lease by giving written notice thereof to
Landlord, in which event this Lease shall terminate as of the date when physical
possession of such portion of the Premises is taken by the condemning authority.
If this Lease is not so terminated upon any such taking or sale, the rent
payable hereunder shall be diminished by a pro rata amount based on the portion
of the Premises taken or sold, and Landlord shall, within a reasonable period
of time following receipt of condemnation proceeds, to the extent Landlord deems
feasible, promptly and diligently restore the Complex and the Premises to
substantially their former condition, but such work shall not exceed the scope
of work done by Landlord in originally constructing the Complex and the scope of
the work in the Premises as described in the Work Agreement, nor shall Landlord
in any event be required to spend for such work an amount in excess of the
amount received by Landlord as compensation for such damage. All amounts awarded
upon a taking of any part or all of the Complex or the Premises shall belong to
Landlord, and Tenant shall not be entitled to and expressly waives all claim to
any such compensation. However, if a portion of the award is specifically
allocated to Tenant's property and moving and relocation expenses, Tenant shall
be entitled to such portion of the award.

                                       23
<PAGE>   23

       25.    DAMAGES FROM CERTAIN CAUSES. Landlord shall not be liable to
Tenant for any loss or damage to any property or person occasioned by theft,
fire, act of God, public enemy, injunction, riot, strike, insurrection, war,
court order, requisition, or order of governmental body or authority or by any
other cause beyond the reasonable control of Landlord. Nor shall Landlord be
liable for any damage or inconvenience which may arise through repair or
alteration of any part of the Complex or Premises except for damage caused by
the gross negligence or intentional misconduct of Landlord or its agents. Except
as set forth in Sections captioned "Casualty Damage" and "Condemnation" and
Section 8(b) above, the causes of loss or damage set forth in this Section shall
not affect the continuation or validity of this Lease or Tenant's obligation to
pay rent hereunder.

       26.    EVENTS OF DEFAULT/REMEDIES.

       (a)    The following events shall be deemed to be Events of Default by
Tenant under this Lease:

              i)     Tenant shall fail to comply with any provision of this
       Lease (or any other agreement between Landlord and Tenant) requiring the
       payment of money and such failure shall continue for a period of five (5)
       days following written notice thereof from Landlord to Tenant of such
       default; provided, however, that in no event shall Tenant be entitled to
       more than two (2) such notices during any twelve (12) month period;

              ii)    Tenant shall violate or fail to perform any other term,
       condition, covenant or agreement to be performed or observed by Tenant
       under this Lease, all of which shall be deemed material and such failure
       shall continue for more than thirty (30) days following notice thereof
       from Landlord to Tenant, said thirty-day period to be increased by an
       additional thirty (30) days if Tenant shall have commenced and diligently
       proceeded to cure such default within said initial thirty-day period;

              iii)   the leasehold hereunder demised shall be taken on execution
       or other process of law in any action against Tenant or Tenant shall
       become insolvent or unable to pay its debts as they become due, or Tenant
       notifies Landlord that it anticipates either condition;

              iv)    Tenant shall fail to move into and take possession of the
       Premises when the Premises are ready for occupancy in accordance with the
       terms hereof, or Tenant shall at any time vacate or abandon the Premises
       without Landlord's prior written approval; however, Landlord will not
       accelerate the rent due under this Lease if Tenant vacates the Premises
       and does not find a suitable assignee or subtenant provided Tenant
       continues to pay rent and is not otherwise in default under this Lease
       and gives thirty (30) days' advance written notice to Landlord of
       Tenant's intention to vacate the space;

                                       24
<PAGE>   24

              v)     Tenant, any guarantor of this Lease ("Guarantor"), or any
       parent or holding company of Tenant (if Tenant is a corporation) files a
       petition under any section or chapter of the Title 11 of the United
       States Code, as amended, or under any similar existing or subsequently
       enacted law or statute of the United States or any State thereof, or a
       petition shall be filed against Tenant or any of said entities or persons
       under any such statute and such petition is not dismissed or vacated
       within ninety (90) days from the filing thereof; or

              vi)    a receiver or trustee shall be appointed for Tenant's
       leasehold interest in the Premises or for all or a substantial part of
       the assets of Tenant or any Guarantor and such order of appointment is
       not dismissed or vacated within ninety (90) days from the entry of such
       order.

       (b)    If an Event of Default shall have occurred, Landlord shall have
the right, at its sole option, to terminate this Lease. With or without
terminating this Lease, Landlord may re-enter and take possession of the
Premises and the provisions of this Section shall operate as a notice to quit;
and any other notice to quit or notice of Landlord's intention to re-enter the
Premises being hereby expressly waived. If necessary, Landlord may proceed to
recover possession of the Premises under and by virtue of the laws of the
Commonwealth of Virginia, or by such other proceedings, including re-entry and
possession, as may be applicable. If Landlord elects to terminate this Lease,
everything contained in this Lease on the part of Landlord to be done and
performed shall cease without prejudice, however, to the right of Landlord to
recover from Tenant all rent and other sums accrued up to the time of
termination or recovery of possession by Landlord, whichever is later. Whether
or not this Lease is terminated by reason of Tenant's default, the Premises may
be relet by Landlord for such rent and upon such terms as Landlord deems
reasonable under the circumstances and, if the full rental provided herein plus
the costs, expenses and damages described below shall not be realized by
Landlord, Tenant shall be liable for all damages sustained by Landlord,
including, without limitation, deficiency in Base Rental and additional rent,
reasonable attorneys' fees, brokerage fees, and the expenses of placing the
Premises in first-class rentable condition. Any damages or loss of rent
sustained by Landlord may be recovered by Landlord, at Landlord's option, at the
time of the reletting, or in separate actions, from time to time, as said damage
shall have been made more easily ascertainable by successive relettings, or, at
Landlord's option, may be deferred until the expiration of the Lease Term, in
which event Tenant hereby agrees that the cause of action shall not be deemed to
have accrued until the date of expiration of the Lease Term. Landlord, however,
shall use reasonable efforts to mitigate its damages hereunder so long as Tenant
cooperates in allowing Landlord to show the Premises to prospective tenants. The
provisions contained in this Section shall be in addition to, and shall not
prevent the enforcement of, any claim Landlord may have against Tenant for
anticipatory breach of this Lease.

       (c)    All rights and remedies of Landlord set forth herein are in
addition to all other rights and remedies available to Landlord at law or in
equity. All rights and remedies available to Landlord hereunder, at law or in
equity, are expressly declared to be cumulative. The

                                       25

<PAGE>   25

exercise by Landlord of any such right or remedy shall not prevent the
concurrent or subsequent exercise of any other right or remedy. No delay in the
enforcement or exercise of any such right or remedy shall constitute a waiver of
any default by Tenant hereunder or of any of Landlord's rights or remedies in
connection therewith. Landlord shall not be deemed to have waived any default by
Tenant hereunder unless such waiver is set forth in a written instrument signed
by Landlord. If Landlord waives in writing any default by Tenant, such waiver
shall not be construed as a waiver of any covenant, condition or agreement set
forth in this Lease except as to the specific circumstances described in such
written waiver.

       (d)    Interest shall accrue on sums due hereunder from Tenant but not
paid, at the lesser of 12% per annum or the highest rate permitted by applicable
law. The provisions of the Section captioned "Holding Over" shall apply with
respect to the period from and after written notice to Tenant of the demand for
payment.

       (e)    In no event shall Tenant have the right to terminate or rescind,
or to withhold, offset or deduct any amount otherwise payable under, this Lease
as a result of Landlord's default of any covenant or agreement contained in this
Lease or as a result of the breach of any promise or inducement hereof, whether
in this Lease or elsewhere. Tenant hereby waives such remedies of termination,
rescission, withholding, offset and deduction, and hereby agrees that Tenant
remedies for default hereunder and for breach of any promise or inducement shall
be limited to a suit for damages and/or injunction. In addition, Tenant hereby
covenants that, prior to the exercise of any such remedies, it will give the
mortgagees on the Complex notice and a reasonable time to cure any default by
Landlord.

       (f)    In addition to all other remedies available to Landlord hereunder,
upon the occurrence of an Event of Default, Landlord may make demand for and
obtain an immediate judgment for all monies due and owing as rent or additional
rent under the terms and conditions of this Lease from the date of default
through the expiration date of the tenancy as set forth in this Lease and in
addition thereto, Landlord shall be entitled to recover immediately all
unamortized costs paid by Landlord as a result of the tenancy, including,
without limitation, tenant improvements, leasing commissions, rent abatements,
and attorneys' fees incurred in negotiating this Lease.

       27.    BANKRUPTCY OF TENANT.

       (a)    If a petition is filed by, or an order for relief is entered
against, Tenant under Chapter 7 of the Bankruptcy Code and the trustee of Tenant
elects to assume this Lease for the purpose of assigning it, the election or
assignment, or both, may be made only if all of the terms and conditions of
subsections (b) and (c) of this Section are satisfied. If the trustee fails to
elect to assume this Lease for the purpose of assigning it within sixty (60)
days after trustee's appointment, this Lease will be deemed to have been
rejected. Landlord shall then immediately be entitled to possession of the
Premises without further obligation to Tenant or the trustee, and this Lease
will be canceled. Landlord's right to be compensated for damages in this
bankruptcy proceeding, however, shall survive.

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<PAGE>   26

       (b)    If Tenant files a petition for reorganization under chapters 11 or
13 of the Bankruptcy Code or a proceeding that is filed by or against Tenant
under any other chapter of the Bankruptcy Code is converted to a chapter 11 or
13 proceeding and Tenant's trustee or Tenant as a debtor-in-possession fails to
assume this Lease within sixty (60) days from the date of the filing of the
petition or the conversion, the trustee or the debtor-in-possession will be
deemed to have rejected this Lease. To be effective, an election to assume this
Lease must be in writing and addressed to Landlord and, in Landlord's business
judgment, all of the following conditions, which Landlord and Tenant acknowledge
to be commercially reasonable, must have been satisfied:

              i)     The trustee or the debtor-in-possession has cured or has
       provided to Landlord adequate assurance, as defined in this section,
       that:

                     (A)    The trustee will cure all monetary defaults under
              this Lease within ten (10) days from the date of the assumption;
              and

                     (B)    The trustee will cure all nonmonetary defaults under
              this Lease within thirty (30) days from the date of assumption.

              ii)    The trustee or the debtor-in-possession has compensated
       Landlord, or has provided to Landlord adequate assurance, as defined in
       this Section, that within ten (10) days from the date of the assumption
       Landlord will be compensated for any pecuniary loss Landlord incurred
       arising from the default of Tenant, the trustee, or the
       debtor-in-possession as recited in Landlord's written statement of
       pecuniary loss sent to the trustee or the debtor-in-possession.

              iii)   The trustee or the debtor-in-possession has provided
       Landlord with adequate assurance of the future performance of each of
       Tenant's obligations under this Lease; provided, however, that the
       trustee or debtor-in-possession will also deposit with Landlord, as
       security for the timely payment of rent, an amount equal to three (3)
       months' Base Rent and additional rent for pass-throughs of Operating
       Expenses and other monetary charges accruing under this Lease.

              iv)    Landlord has determined that the assumption of this Lease
       will not breach any provision in any other lease, mortgage, financing
       agreement, or other agreement by which Landlord is bound relating to the
       Complex.

              v)     For purposes of this section, "adequate assurance" means
       that:

                     (A)    Landlord will determine that the trustee or the
              debtor-in-possession has, and will continue to have, sufficient
              unencumbered assets after the payment of all secured obligations
              and administrative expenses to assure Landlord that the trustee
              or

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<PAGE>   27

              the debtor-in-possession will have sufficient funds to fulfill
              Tenant's obligations under this Lease; and

                     (B)    An order will have been entered segregating
              sufficient cash payable to Landlord and/or a valid and perfected
              first lien and security interest will have been granted in
              property of Tenant, trustee, or debtor-in-possession that is
              acceptable for value and kind to Landlord, to secure to Landlord
              the obligation of the trustee or debtor-in-possession to
              immediately cure any monetary or nonmonetary defaults under this
              Lease.

       (c)    In the event that this Lease is assumed by a trustee appointed for
Tenant or by Tenant as debtor-in-possession under the provisions of subsection
(b) above and, thereafter, Tenant is either adjudicated a bankrupt or files a
subsequent petition for arrangement under chapter 11 of the Bankruptcy Code,
then Landlord may terminate, at its option, this Lease and all of Tenant's
rights under it, by giving written notice of Landlord's election to terminate.

       (d)    If the trustee or the debtor-in-possession has assumed this Lease,
under the terms of subsections (a) or (b) above, to assign or to elect to assign
Tenant's interest under this Lease or the estate created by that interest to any
other person, that interest or estate may be assigned only if Landlord
acknowledges in writing that the intended assignee has provided adequate
assurance, as defined in this subsection (d), of future performance of all of
the terms, covenants, and conditions of this Lease to be performed by Tenant.
For the purposes of this subsection (d), adequate assurance of future
performance means that Landlord has ascertained that each of the following
conditions has been satisfied:

              i)     The assignee has submitted a current financial statement,
       audited by a certified public accountant, that shows a net worth and
       working capital in amounts determined by Landlord to be sufficient to
       assure the future performance by the assignee of Tenant's obligation
       under this Lease.

              ii)    If requested by Landlord, the assignee will obtain
       guarantees, in form and substance satisfactory to Landlord, from one or
       more persons who satisfy Landlord's standards of credit-worthiness.

              iii)   Landlord has obtained all consents or waivers from any
       third party required under any lease, mortgage, financing arrangement, or
       other agreement by which Landlord is bound, to enable Landlord to permit
       the assignment.

       (e)    When, pursuant to the Bankruptcy Code, the trustee or the
debtor-in-possession is obligated to pay reasonable use and occupancy charges
for the use of all or part of the Premises, the charges will not be less than
the Base Rent as defined in this Lease and other monetary obligations of Tenant
for the payment of additional rent.

                                       28

<PAGE>   28

       (f)    Neither Tenant's interest in this Lease nor any estate of Tenant
created in this Lease will pass to any trustee, receiver, assignee for the
benefit of creditors, or any other person or entity, or otherwise by operation
of law under the laws of any state having jurisdiction of the person or property
of Tenant, unless Landlord consents in writing to this transfer. Landlord's
acceptance of rent or any other payments from any trustee, receiver, assignee,
person, or other entity will not be deemed to have waived, or waive, the need to
obtain Landlord's consent or Landlord's right to terminate this Lease for any
transfer of Tenant's interest under this Lease without that consent.

       28.    ENVIRONMENTAL LIABILITY.

       (a)    The term "Hazardous Materials" for purposes hereof shall mean (i)
"hazardous wastes," as defined by the Resource Conservation and Recovery Act of
1976, as amended from time to time, (ii) "hazardous substances," as defined by
the Comprehensive Environmental Response, Compensation and Liability Act of
1980, as amended from time to time, (iii) "toxic substances," as defined by the
Toxic Substances Control Act, as amended from time to time, (iv) "hazardous
materials," as defined by the Hazardous Materials Transportation Act, as amended
from time to time, (v) oil or other petroleum products, (f) any substances whose
presence could be detrimental to the Complex or hazardous to health or the
environment, and (g) any chemical, substance, materials or waste or component
thereof which is now or hereafter listed, defined or regulated as a hazardous or
toxic chemical, substance, materials or waste or component thereof by any
federal, state or local governing or regulatory body having jurisdiction, or
which would trigger any employee or community "right-to-know" requirements
adopted by any such body, or for which any such body has adopted any
requirements for the preparation or distribution of a materials safety data
sheet ("MSDS").

       (b)    Tenant shall not transport, use, store, maintain, generate,
manufacture, handle, dispose, release or discharge any Hazardous Materials.
However, the foregoing provisions shall not prohibit the use, storage or
handling within the Premises of Hazardous Materials customarily used in the
operation of standard office equipment used by Tenant; provided, however, (i)
such Hazardous Materials shall be used and maintained only in such quantities as
are reasonably necessary for such equipment use strictly in accordance with
applicable law, highest prevailing standards, and the manufacturers'
instructions therefor, (ii) such Hazardous Materials shall not be disposed of,
released or discharged in the Complex, and shall be transported to and from the
Premises in compliance with all applicable laws, and as Landlord shall
reasonably require, (iii) if any applicable law or Landlord's trash removal
contractor requires that any such Hazardous Materials be disposed of separately
from ordinary trash, Tenant shall make arrangements at Tenant's expense for such
disposal directly with a qualified and licensed disposal company at a lawful
disposal site (subject to scheduling and approval by Landlord), and (d) any
remaining such Hazardous Materials shall be completely, properly and lawfully
removed from the Complex upon expiration or earlier termination of this Lease.

       (c)    Tenant shall promptly notify Landlord of: (i) any enforcement,
cleanup or other regulatory action taken or threatened by any governmental or
regulatory authority with respect

                                       29

<PAGE>   29

to the presence of any Hazardous Materials on the Premises or the migration
thereof from or to other property, (ii) any demands or claims made or threatened
by any party relating to any loss or injury resulting from any Hazardous
Materials on the Premises, (iii) any release, discharge or nonroutine, improper
or unlawful disposal or transportation of any Hazardous Materials on or from the
Premises or in violation of this Section, and (iv) any matters where Tenant is
required by law to give a notice to any governmental or regulatory authority
respecting any Hazardous Materials on the Premises. Landlord shall have the
right (but not the obligation) to join and participate, as a party, in any legal
proceedings or actions affecting the Premises initiated in connection with any
environmental, health or safety law. At such times as Landlord may reasonably
request, Tenant shall provide Landlord with a written list, certified to be true
and complete, identifying any Hazardous Materials then used, stored, or
maintained upon the Premises, the use and approximate quantity of each such
material, a copy of any MSDS issued by the manufacturer therefor, and such other
information as Landlord may reasonably require or as may be required by law.

       (d)    If any Hazardous Materials are released, discharged or disposed of
by Tenant or any other occupant of the Premises, or their employees, agents,
invitees or contractors, on or about the Complex in violation of the foregoing
provisions, Tenant shall immediately, properly and in compliance with applicable
laws clean up, remediate and remove the Hazardous Materials from the Complex and
any other affected property and clean or replace any affected personal property
(whether or not owned by Landlord), at Tenant's expense (without limiting
Landlord's other remedies therefor). Tenant shall indemnify and hold Landlord,
Landlord's directors, officers, employees and agents harmless from and against
any and all claims, demands, liabilities, losses, damages, penalties and
judgments directly or indirectly arising out of or attributable to a violation
of the provisions of this Section by Tenant, Tenant's occupants, employees,
contractors or agents. Any clean up, remediation and removal work shall be
subject to Landlord's prior written approval (except in emergencies), and shall
include, without limitation, any testing, investigation, and the preparation and
implementation of any remedial action plan required by any government body
having jurisdiction or reasonably required by Landlord. If Landlord or any
lender or governmental body arranges for any tests or studies showing that this
Section has been violated, Tenant shall pay for the costs of such tests.

       (e)    Landlord represents and warrants to Tenant that to the best of the
knowledge of Renee T. Bergeron, Landlord's asset manager, in reliance solely
upon the Phase I Environmental Site Assessment dated January 11, 1995, prepared
by ATEC Associates, Inc., and without any other investigation by Landlord or
inquiry of the tenants in the Complex, (A) the Complex does not contain, and
there is not located on or about the Complex, any Hazardous Materials in amounts
in violation of any environmental laws or ordinances; (B) no part of the Complex
is currently used for the use, storage, treatment, production, manufacture,
generation, transportation, release or disposal of Hazardous Materials in
amounts in violation of any environmental laws or ordinances.

       (f)    The provisions of this Section shall survive the expiration or
earlier termination of this Lease.

                                       30

<PAGE>   30

       29.    QUIET ENJOYMENT. Tenant shall, and may peacefully have, hold, and
enjoy the Premises, subject to the other terms hereof, provided that Tenant pays
the rent and other sums herein recited to be paid by Tenant and performs all of
Tenant's covenants and agreements herein contained. This covenant and any and
all other covenants of Landlord shall be binding upon Landlord and its
successors only with respect to breaches occurring during its or their
respective periods of ownership of the Landlord's interest hereunder.

       30.    HOLDING OVER. In the event that Tenant shall not immediately
surrender the Premises on the date of the expiration of the Lease Term, Tenant
shall become a tenant by the month at one and one-half times the Base Rent and
all additional rent in effect during the last month of the Lease Term. Said
monthly tenancy shall commence on the first day following the expiration of the
Lease Term. As a monthly tenant, Tenant shall be subject to all the terms,
conditions, covenants and agreements of this Lease, except as to the amount of
the Base Rent, which shall be in the amount specified in this Section. Tenant
shall give to Landlord at least thirty (30) days' written notice of any
intention to quit the Premises, and Tenant shall be entitled to thirty (30)
days' written notice to quit the Premises, unless Tenant is in default
hereunder, in which event Tenant shall not be entitled to any notice to quit,
the usual thirty (30) days' notice to quit being hereby expressly waived.
Notwithstanding the foregoing provisions of this Section, in the event that
Tenant shall hold over after the expiration of the Lease Term, and if Landlord
shall desire to regain possession of the Premises promptly at the expiration of
the Lease Term, then at any time prior to Landlord's acceptance of rent from
Tenant as a monthly tenant hereunder, Landlord, at its option, may forthwith
re-enter and take possession of the Premises without process, or by any legal
process in force in the Commonwealth of Virginia. To the extent permitted by
law, Landlord may accept rent in the holdover amount and concurrently commence
legal proceedings to regain possession of the Premises.

       31.    SUBORDINATION AND ATTORNMENT.

       (a)    Provided Landlord obtains for the benefit of Tenant from
Landlord's mortgagee or ground lessor such mortgagee's or ground lessor's
standard nondisturbance agreement reasonably acceptable to Tenant, this Lease is
and shall remain subject and subordinate to the lien of any and all current and
future first mortgages and/or any ground leases (which term "mortgages" shall
include both construction and permanent financing and shall include deeds of
trust and similar security instruments) which may now encumber the Complex or
the land on which the Complex is located, and to all and any renewals,
extensions, modifications, consolidations, recastings or refinancings thereof.
At any time after the execution of this Lease, the holder of any mortgage to
which this Lease is subordinate shall have the right to declare this Lease to be
superior to the lien of such mortgage, and Tenant agrees to execute all
documents required by such holder in confirmation thereof.

       (b)    In the event that Tenant should fail to execute any instrument of
nondisturbance and subordination herein required to be executed by Tenant within
fifteen (15) days of Landlord's demand, Tenant hereby irrevocably constitutes
Landlord as its attorney-in-fact to

                                       31

<PAGE>   31

execute such instrument in Tenant's name, place and stead, it being agreed that
such power is one coupled with an interest.

       (c)    In the event any proceedings are brought for the foreclosure of
any mortgage encumbering the Complex or the termination of any ground lease
affecting the Complex, Tenant shall attorn to the purchaser at such foreclosure
sale or any ground lessor, as the case may be, if requested to do so by such
party, and shall recognize such party as the Landlord, under this Lease, and
Tenant waives the provisions of any statute or rule of law, now or hereafter in
effect, which may give or purport to give Tenant any right to terminate or
otherwise adversely affect this Lease and the obligations of Tenant hereunder in
the event any such foreclosure proceeding is prosecuted or completed.

       (d)    Landlord represents and warrants to Tenant that Landlord owns the
Complex in fee simple and as of the date of the execution and delivery of this
Lease, the Complex is not encumbered by a ground lease or the lien of any
mortgage or deed of trust.

       32.    LANDLORD'S LIEN. Tenant hereby grants to Landlord a lien and
security interest on all property of Tenant now or hereafter placed in or upon
the Premises, and such property shall be and remain subject to such lien and
security interest of Landlord for payment of all rent and other sums agreed to
be paid by Tenant herein. The provisions of this Section relating to such lien
and security interest shall constitute a security agreement under and subject to
Virginia Uniform Commercial Code so that Landlord shall have and may enforce a
security interest on all property of Tenant now or hereafter placed in or on the
Premises, in addition to and cumulative of Landlord's liens and rights provided
by law or by the other terms and provisions of this Lease. Tenant agrees to
execute as debtors such financing statement or statements as Landlord may now or
hereafter request. Landlord may at its election at any time file a copy of this
Lease as a financing statement.

       33.    ATTORNEYS' FEES. In the event either party defaults in the
performance of any of the terms of this Lease and the other party employs an
attorney in connection therewith, the defaulting party agrees to pay the
prevailing party's reasonable attorneys' fees.

       34.    NO IMPLIED WAIVER. No provision of this Lease shall be deemed to
have been waived by Landlord unless such a waiver be in writing signed by
Landlord. The failure of Landlord to insist at any time upon the strict
performance of any covenant or agreement or to exercise any option, right, power
or remedy contained in this Lease shall not be construed as a waiver or a
relinquishment thereof for the future. No payment by Tenant or receipt by
Landlord of a lesser amount than the monthly installment of rent due under this
Lease shall be deemed to be other than on account of the earliest rent due
hereunder, nor shall any endorsement or statement on any check or any letter
accompanying any check or payment of rent be deemed an accord and satisfaction,
and Landlord may accept such check or payment without prejudice to Landlord's
right to recover the balance of such rent or pursue any other remedy in this
Lease provided. No agreement to accept a surrender of this Lease shall be valid
unless in a writing

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<PAGE>   32

signed by Landlord. The receipt by Landlord of rent with knowledge of the breach
of any covenant of this Lease shall not be deemed a waiver of such breach.

       35.    PERSONAL LIABILITY. The liability of Landlord to Tenant for any
default by Landlord under the terms of this Lease shall be limited to the
interest of Landlord in the Complex, Tenant shall look solely to Landlord's
interest in the Complex for the recovery of any judgment from Landlord, it being
intended that neither Landlord nor any partner or principal of Landlord nor any
other property disclosed or undisclosed of such partners or principals shall be
personally liable for any judgment or deficiency.

       36.    SECURITY DEPOSIT.

       (a)    The Security Deposit shall be held by Landlord as security for the
performance by Tenant of Tenant's covenants and obligations under this Lease, it
being expressly understood that the Security Deposit shall not be considered as
advance payment of rent or a measure of Tenant's damages in case of default by
Tenant. The Security Deposit shall be in the form of an unconditional and
irrevocable letter of credit substantially in the form of Exhibit E attached
hereto, from a federally insured bank in the Washington, D.C. metropolitan area,
with a term coterminous with the Lease Term as it may be extended (or if
required by such bank, in annual installments, the last of which expires no
earlier than the Lease Term as it may be extended), and naming Landlord as
beneficiary. Tenant may at any time substitute cash for the letter of credit.

       (b)    Landlord may from time to time during the continuance of an Event
of Default, without notice to Tenant, draw upon the Security Deposit (either by
drawing upon the letter of credit or withdrawing cash) any amount up to the
amount required to cure the Event of Default, and such draw shall be deemed to
cure the Event of Default, unless Tenant fails timely to perform its obligation
under the next sentence. Landlord shall promptly notify Tenant of any draw on
the Security Deposit pursuant to this subsection (b), and Tenant shall, within
five (5) days of its receipt of such notice, restore the Security Deposit to the
required Security Deposit amount. Tenant's failure to do so shall constitute a
Event of Default hereunder.

       (c)    Within approximately sixty (60) days after the later of the
expiration or earlier termination of the Lease Term, Landlord shall return the
Security Deposit less such portion thereof as Landlord shall have used to
satisfy Tenant's obligations under this Lease.

       (d)    If Landlord transfers the Security Deposit to any transferee of
the Complex or of Landlord's interest therein, then such transferee shall be
liable to Tenant for the return of the Security Deposit. Landlord shall be
released from all liability for the return of the Security Deposit provided such
transferee assumes Landlord's obligations under this Lease. The holder of any
mortgage shall not be liable for the return of the Security Deposit unless such
holder actually receives the Security Deposit.

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<PAGE>   33

       (e) Tenant shall cooperate with Landlord to obtain an amendment or
replacement of the letter of credit if Landlord transfers the Security Deposit
to a new owner of the Building or of Landlord's interest therein or if Landlord
receives notice from the issuer of the letter of credit that the letter of
credit will not be renewed. In such event, Landlord may draw down the letter of
credit, and the cash proceeds thereof shall be held as the Security Deposit in
accordance with this Lease if Tenant does not obtain such amendment or
replacement within twenty (20) days of Landlord's written request therefor. If
at any time, the letter of credit is drawn down pursuant to this subsection
(e), Tenant shall not be deemed in default and may, at Tenant's option, replace
the cash Security Deposit with a new letter of credit substantially in the form
of Exhibit E.

       (f) Any cash deposited by Tenant as part of the Security Deposit or the
cash drawn by Landlord pursuant to subsection (e) shall be deposited by
Landlord in a federally insured bank. Such account shall bear interest at money
market rates and the interest shall become a part of the Security Deposit.
Tenant shall be responsible for any income tax due for any interest earned on
the Security Deposit. Unless otherwise provided by mandatory non-waivable law
or regulation, Landlord may commingle the Security Deposit with Landlord's
other funds. In no event shall a cash Security Deposit be deemed to be trust
funds.

       (g) Tenant hereby pledges, assigns, conveys, and transfers to Landlord
a lien upon, security title to, a security interest in, and right of setoff
against the Security Deposit and any other money now or hereafter deposited by
Tenant with Landlord. No lien, security title, security interest, or right of
setoff shall be deemed to have been waived by any act or conduct on the part of
Landlord, or by any neglect to exercise such right of setoff or to enforce such
lien, security title or security interest, or by any delay in so doing, and
every lien, security title, security interest, and right of setoff shall
continue in full force and effect until specifically waived or released by an
instrument in writing executed by Landlord.

       (h) Provided no Event of Default shall have occurred during the first
forty-eight (48) months of the Lease Term and if the Security Deposit has not
already been reduced pursuant to subsection (i) below, the amount of the
Security Deposit shall be reduced to Five Hundred Thousand Dollars ($500,000)
as of the beginning of the forty-ninth (49th) month of the Lease Term, and
such reduced Security Deposit shall be held by Landlord through the
expiration of the Lease Term or any extension thereof in accordance with the
terms of this Lease unless it is further reduced pursuant to subsection (i)
below.

       (i) Provided no Event of Default shall have occurred, at such time as
Tenant maintains a net worth of Five Million Dollars ($5,000,000) for
twenty-four (24) consecutive months, the Security Deposit shall be reduced to
the amount of the Base Rent in effect for the month immediately following the
twenty-fourth (24th) month of such maintenance period. Such reduced Security
Deposit shall be held by Landlord through the expiration of the Lease Term or
any extension thereof in accordance with the terms of this Lease. To
demonstrate that the foregoing stabilized net worth has been attained, Tenant
shall provide Landlord with its audited financial statements covering the
twenty-four (24) month period. The financial statements shall be prepared by
a major independent certified public accounting firm in accordance with
generally

                                    34
<PAGE>   34

accepted accounting principles consistently applied. The financial statements
shall demonstrate to Landlord's reasonable satisfaction that Tenant's net worth
is based on, by way of example, such assets as Class A common shares and
retained earnings in lieu of other assets such as convertible stock which would
be convertible in a way which would reduce Net Worth. In evaluating Tenant's net
worth, Landlord may request, and Tenant shall provide, balance sheets, profit
and loss statements and income and expense statements with such detailed
supporting schedules as Landlord may reasonably request.

       37. FINANCING REQUIREMENTS. In the event that any person, including but
not limited to any bank, insurance company, university, pension or welfare fund,
savings and loan association, real estate investment trust, business trust, or
other financial institution providing financing for the Complex requires, as a
condition of such financing, that modifications to this Lease be obtained, and
provided that such modifications (i) do not adversely affect Tenant's use of the
Premises as herein permitted, (ii) do not materially alter the approved
architectural plans and specifications or the description of Landlord's work in
Exhibit B, and (iii) do not increase the rentals and other sums required to be
paid by Tenant hereunder, Landlord shall submit such required modifications to
Tenant, and if Tenant does not enter into and execute a written amendment hereto
incorporating such required modifications within thirty (30) days after the same
have been submitted to Tenant by Landlord, Landlord shall have the right, at its
sole option, (1) to cancel this Lease, (2) to sign on behalf of Tenant pursuant
to a power of attorney, which is hereby expressly granted to Landlord by Tenant,
or (3) to declare an Event of Default under this Lease. Such options shall be
exercisable by Landlord giving Tenant written notice of the option elected.
Landlord's exercise of any of the foregoing rights may not materially impair
Tenant's use and enjoyment of the Premises or rights under this Lease, nor
materially impair Tenant's ingress and egress to and from the Premises.

       38. ESTOPPEL CERTIFICATE. Tenant shall, at any time and from time to
time, upon not less than five (5) days' prior written notice by Landlord,
execute, acknowledge and deliver to Landlord a statement in writing (i)
certifying that this Lease is unmodified and in full force and effect (or if
there have been modifications, that the Lease is in full force and effect as
modified and stating the modifications); (ii) stating the dates to which the
rent and any other charges hereunder have been paid by Tenant; (iii) stating
whether or not, to the best knowledge of Tenant, Landlord is in default in the
performance of any covenant, agreement or condition contained in this Lease, and
if so, specifying the nature of such default; (iv) stating that all Tenant work
has been satisfactorily completed, or if not, a list of items excepted; (v) any
other certification reasonably required by Landlord; and (vi) stating the
address to which notices to Tenant are to be sent. Any statement delivered by
Tenant may be relied upon by any owner of the Complex or the land upon which it
is situated, any prospective purchaser of the Complex or such land, or
prospective mortgagee of the Complex or such land or of Landlord's interest
therein, or any prospective assignee of any such mortgagee.

       39. CERTAIN RIGHTS RESERVED. Landlord hereby reserves to itself and its
successors and assigns the following rights (all of which are hereby consented
to by Tenant): (i) to change the street address and/or name of the Building
and/or the Complex and/or the arrangement and/or location of entrances,
passageways, doors, doorways, corridors, elevators, stairs, toilets,

                                    35
<PAGE>   35

or other public parts of the Building and/or the Complex and to change the
design or configuration of the Building or the Complex; (ii) to erect, use and
maintain pipes and conduits in and through the Premises; and (iii) to grant to
anyone the exclusive right to conduct any particular business or undertaking
in the Building or the Complex. Landlord may exercise any or all of the
foregoing rights without being deemed to be guilty of an eviction, actual or
constructive, or a disturbance or interruption of the business of Tenant or
of Tenant's use or occupancy of the Premises.

       40. RELOCATION. [intentionally omitted]

       41. BROKERS. Landlord recognizes Cassidy and Pinkard Property Services,
L.L.C. (formerly known as "Americorp Realty"), and Randall H. Hagner & Company
as the sole brokers procuring this Lease and shall pay said brokers a commission
therefor pursuant to separate agreements between said brokers and Landlord.
Landlord and Tenant each represent and warrant to the other that, except as
provided above, neither of them has employed or dealt with any broker, agent, or
finder in carrying on the negotiations relating to this Lease. Landlord shall
indemnify and hold Tenant harmless, and Tenant shall indemnify and hold Landlord
harmless, from and against any claims for brokerage or other commissions arising
from or out of any breach of the foregoing representation and warranty by the
respective indemnitor. Without limiting the foregoing, Tenant agrees to,
immediately upon demand, pay and/or cause to be released of record and otherwise
any lien filed against the Complex or any portion thereof by any broker or
agent other than those listed above to the extent of their services provided in
procuring this Lease, due to, or allegedly due to, any action of Tenant, or to
post a bond with respect to such lien in an amount, and upon terms, and with a
bonding entity, reasonably satisfactory to Landlord.

       42. MISCELLANEOUS.

       (a) ENTIRE AGREEMENT. This Lease contains and embodies the entire
agreement of the parties hereto, and no representations, inducements, or
agreements, oral or otherwise, not contained in this Lease shall be of any
force or effect. This Lease may not be modified or changed in whole or in part
in any manner other than by an instrument in writing duly signed by the
parties hereto.

       (b) NO REPRESENTATIONS. Tenant acknowledges that neither Landlord nor
any broker, agent or employee of Landlord has made any representations or
promises with respect to the Premises, the Building, the Complex, or the land
on which the Complex is located, except as herein expressly set forth, and no
rights, privileges, easements or licenses are acquired by Tenant except as
herein expressly set forth.

       (c) AUTHORITY. Tenant represents and warrants to Landlord that (i) it is
a Delaware corporation duly authorized to conduct business in the Commonwealth
of Virginia and (ii) the person executing this Lease on behalf of Tenant has
been duly authorized to do so.

                                    36
<PAGE>   36

       (d) NOTICES. Landlord is a nonresident of the Commonwealth of Virginia
and has appointed Edward R. Parker, having an address at c/o CT Corporation,
5511 Staples Mill Road, Richmond, Virginia 23228, as its appointed agent to
receive service of process, notices, orders or demands. All notices or other
communications hereunder shall be in writing and shall be deemed duly given if
(i) delivered in person with a signed receipt therefor, (ii) sent by a
nationally recognized overnight delivery service, such as FedEx, with delivery
fees prepaid or billed to sender, or (iii) sent by certified or registered
mail, return receipt requested, postage prepaid, to the following addresses:
(A) if to Landlord, at SSR Realty Advisors, Inc. (formerly known as MetLife
Realty Group, Inc.), One North Broadway, Suite 500, White Plains, New York
10601, with copy to Cassidy & Pinkard Property Services, L.L.C., American
Center, 8300 Boone Blvd., Suite 100, Vienna, Virginia 22182; (B) if to Tenant,
before occupancy, at c/o Asghar D. Mostafa, 10026 Scenic View Terrace, Vienna,
Virginia 22182, and after occupancy at the Premises. Either party may change
its address for the giving of notices by notice given in accordance with this
Section.

       (e) TRANSFERS BY LANDLORD. Landlord shall have the right to transfer and
assign, in whole or in part, all its rights and obligations hereunder and in the
Complex and property referred to herein, and in such event and upon such
transfer, Landlord shall be released from any further obligations hereunder. It
shall be deemed and construed as a covenant running with the land without
further agreement between the parties or their successors in interest, or
between the parties and the transferee of the Complex or of the land on which
the Complex is located that the transferee has assumed and agreed to carry out
any and all covenants and obligations of Landlord hereunder. Tenant agrees to
look solely to such successor in interest of Landlord for the performance of
such obligations.

       (f) SEVERABILITY. If any term of provision of this Lease, or the
application thereof to any person or circumstances shall, to any extent, be
invalid or unenforceable, the remainder of this Lease, or the application of
such term or provision to persons or circumstances other than those as to which
it is held invalid or unenforceable, shall not be affected thereby, and each
term and provision of this Lease shall be valid and enforceable to the fullest
extent permitted by law.

       (g) CALENDAR DAYS/(BUSINESS DAYS. As used in this Lease and the exhibits
hereto, all references to "days" shall be calendar days unless business days
are specified.

       (h) SUCCESSORS AND ASSIGNS. The provisions of this Lease shall be
binding upon, and shall inure to the benefit of, the parties hereto and each
of their respective representatives, successors and assigns, subject to the
provisions hereof prohibiting or restricting assignment or subletting by
Tenant. If more than one person is liable under this Lease, the liability of
such persons shall be joint and several.

       (i) RECORDATION. Tenant agrees not to record this Lease or any
memorandum or copy thereof.

                                    37

<PAGE>   37
       (j) FORCE MAJEURE. Whenever a period of time is herein prescribed for
the taking of any action by Landlord, Landlord shall not be liable or
responsible for, and there shall be excluded from the computation of such
period of time, any delays due to strikes, riots, acts of God, unusually severe
weather, shortages of labor or materials, acts of war or civil disobedience,
the act or failure to act of any public service or utility provider,
governmental laws, regulations or restrictions, or any other cause whatsoever
beyond the control of Landlord.

       (k) TIME OF PERFORMANCE. Except as expressly otherwise herein provided,
with respect to all required acts of Landlord and Tenant, time is of the
essence in this Lease.

       (l) NO PARTNERSHIP. Nothing contained in this Lease shall be construed
as creating a partnership or joint venture of or between Landlord and Tenant,
or to create any other relationship between the parties hereto other than that
of Landlord and Tenant.

       (m) EFFECT OF DELIVERY OF THIS LEASE. Landlord has delivered a copy of
this Lease to Tenant for Tenant's review only, and the delivery hereof does not
constitute an offer to Tenant or option. This Lease shall not be effective
until a copy executed by both Landlord and Tenant is delivered to and accepted
by Landlord.

       (n) CONSTRUCTION. Tenant acknowledges that Tenant and its
representatives have participated in the negotiation and drafting of this
Lease. This Lease shall not be construed more strictly against Landlord on the
grounds that this Lease has been prepared by Landlord and/or its counsel.

       (o) COUNTERPARTS. This Lease may be executed in multiple counterparts,
each of which shall be deemed an original and all of which together shall
constitute one and the same document.

       (p) HEADINGS. Section headings are used herein for the convenience of
reference and shall not be considered when construing or interpreting this
Lease.

       (q) EXHIBITS. The Exhibits attached hereto (including, without
limitation, the Work Agreement attached hereto as Exhibit B) are incorporated
herein and made a part of this Lease for all purposes.

       (r) WAIVER OF JURY TRIAL. Landlord and Tenant each hereby waive trial by
jury in any action, proceeding or counterclaim brought by either of them
against the other in connection with any matter arising out of or in any way
connected with this Lease, the relationship of Landlord and Tenant hereunder,
Tenant's use or occupancy of the Premises, and/or any claim or injury or
damage.

                                       38

<PAGE>   38

       (s) CONSENT TO JURISDICTION AND FORUM. Any litigation in connection
with, or arising out of, this Lease shall be brought in the state or federal
courts for the County of Fairfax, Virginia. Landlord and Tenant hereby consent
to such court's exercise of personal jurisdiction over them. Tenant irrevocably
appoints Michael M. Mannix, Esquire, having an address at Stauffer, Mannix,
Rommel, Decker and Delany, 8300 Greensboro Drive, McLean, Virginia 22102, as
Tenant's agent for receipt of service of process on Tenant's behalf in
connection with any suit, writ, attachment, execution or discovery or
supplementary proceedings in connection with the enforcement of this Lease.
Service shall be effected by any means permitted by the court in which any
action is filed, or, at Landlord's option, by mailing process, postage prepaid,
by certified mail, return receipt requested, either to Tenant's agent at the
foregoing address or to Tenant at Tenant's address set forth in the Section
captioned "Notices". Service shall be deemed effective upon receipt. Tenant may
designate a change of address or agent for purposes of this Section by written
notice to Landlord in accordance with the provisions of the Section captioned
"Notices" at least ten (10) days before such change of address or agent is to
become effective.

          (t) GOVERNING LAW. This Lease and the rights and obligations of the
parties hereto shall be interpreted, construed, and enforced in accordance with
the laws of the Commonwealth of Virginia.

          IN WITNESS WHEREOF, Landlord and Tenant have executed this Lease as
of the day and year first above written.

                                     TENANT:

WITNESS or ATTEST:                   ADVANCED SWITCHING COMMUNICATIONS, INC.,
                                      a Delaware corporation

    [SIG]                          By:  /s/ ASGHAR D. MOSTAFA [SEAL]
--------------                         ----------------------
                                       Asghar D. Mostafa
                                       President and CEO

                                     LANDLORD:

WITNESS or ATTEST:                   MET LIFE INTERNATIONAL REAL ESTATE EQUITY
                                     SHARES, INC.,
                                      a Delaware corporation

    [SIG]                          By:  T. ANDREW BEHYMER    [SEAL]
---------------                        ---------------------
                                       Name:  T. Andrew Behymer
                                       Title: Vice President

                                       39

<PAGE>   39

                             AMERICAN CENTER LEASE

                                LIST OF EXHIBITS

 EXHIBIT A           -        Outline of Demised Premises

 EXHIBIT B           -        Work Agreement

 EXHIBIT C           -        Declaration of Commencement Date

 EXHIBIT D           -        Rules & Regulations

 EXHIBIT E           -        Form of Letter of Credit

                                       40
<PAGE>   40
                                    EXHIBIT A
                          Outline of Demised Premises

<PAGE>   41

                                    EXHIBIT B
                                 WORK AGREEMENT

       This Work Agreement governs the terms and conditions for the design and
reconstruction of the existing tenant improvements for Tenant's use (the "Tenant
Improvements") and the Schedule of Responsibilities (as hereinafter defined) for
Landlord and Tenant to complete the Tenant Improvements.

       Unless otherwise specifically provided in this Work Agreement, all
capitalized terms in this Work Agreement shall have the meanings ascribed
thereto in the Lease. This Work Agreement is incorporated by reference into the
Lease. In the event of any inconsistencies between this Work Agreement and other
terms of the Lease, the terms of this Work Agreement shall control and take
precedence.

       1. SPACE PLAN. Attached hereto is as Exhibit B-1 and made a part hereof
by this reference are the Space Plan and Construction Specifications
(collectively, the "Space Plan") prepared by The M Group and approved by Tenant
and Landlord for the Tenant Improvements for the renovation of the Phase I Space
and the Phase II Space.

       2. EXISTING CONDITION OF THE PREMISES. Tenant acknowledges that Tenant
has thoroughly inspected the Premises. In preparing the Space Plan, Tenant has
taken into account the condition of the Premises as of the date of the Lease and
accepts the Premises in their "as is" condition, except latent defects.

       3. TURN-KEY CONSTRUCTION.

       (a) Landlord shall construct the Tenant Improvements shown on the Space
Plan on a turn-key basis (including payment for the Space Plan, Working Drawings
(as hereinafter defined), and building permits) at no charge to Tenant. The
Space Plan includes allowances (the "Allowances") for certain fixtures and
materials and the related labor costs that will be provided as part of the
Tenant Improvements.

       (b) In the event Tenant elects to improve the Premises with materials the
quality or quantity of which is in excess of the Allowances for such materials
specified in the Space Plan and such materials and/or the additional labor
required will result in a higher cost to Landlord, the cost of such improvements
(the "Excess Improvements") shall be a Tenant Cost (as hereinafter defined).
Tenant shall not be entitled to any credit in the event Tenant elects to use
materials the quantity or cost of which is less than the Allowances therefor.

       (c) Tenant shall incur no cost for the Tenant Improvements provided that
none of the Allowances are exceeded, there are no Excess Improvements, and there
are no Tenant Delays (as hereinafter defined). Tenant shall not be allowed any
credit for unused Allowances.

       (d) Any amount that Tenant is required to pay under this Agreement shall
be referred to as a "Tenant Cost". Any Tenant Costs shall be deemed rent under
the Lease. Landlord may reasonably estimate Tenant Costs in advance, in which
case, Tenant shall deposit such estimated amount with Landlord. If such
estimated amount exceeds the actual amount of the Tenant Costs, Tenant shall
receive a refund of the difference. If the actual amount shall exceed the
estimated amount, Tenant shall pay the difference to Landlord within ten (10)
days after receipt of an invoice therefor from Landlord.

       4. WORKING DRAWINGS.

       (a) Working drawings (the "Working Drawings") for the Tenant Improvements
shall comprise the final architectural, mechanical and electrical plans and
specifications approved by Landlord and Tenant, which shall be the basis for
performance of all work in the Premises

<PAGE>   42

herein contemplated. Except as described below, the Working Drawings shall be at
1/8" = 1' scale and will include architectural and engineering drawings and
specifications as well as notes necessary for pricing, permits and construction
and calculations of quantities of items. Working Drawings will include but not
be limited to the following, if applicable:

       (i)    partition plan at 1/8" scale;

       (ii)   reflected ceiling and lighting plan;

       (iii)  electrical and telephone outlet plan;

       (iv)   mechanical and plumbing plan;

       (v)    finish and color schedule;

       (vi)   door and hardware schedule including jamb details at 1-1/2" scale
              for doors and/or jambs if required; and

       (vii)  all other architectural and engineering detail drawings and
              specifications reasonably necessary to accomplish the work
              including detailed representation and/or elevations of all special
              conditions at 1-1/2" scale.

       (b) Promptly after the execution and delivery of the Lease, Landlord's
architect and engineer shall commence preparation of the Working Drawings, which
shall be based on the Space Plan. Landlord's contractor, PCW Construction, Inc.
("Landlord's Contractor"), shall deliver the Working Drawings to Tenant for
written approval promptly after any pricing relating to Excess Improvements in
the Space Plan have been determined. Within seventy-two (72) hours after
Tenant's receipt of the Working Drawings, Tenant shall notify Landlord in
writing whether (i) Tenant desires any changes in the Working Drawings and (ii)
Tenant's approval or conditional approval of the Working Drawings. If Tenant has
requested pricing for Excess Improvements, Tenant shall also notify Landlord in
writing that the pricing therefor is acceptable and that Tenant acknowledges its
obligation to pay for the Excess Improvements as a Tenant Cost and Tenant will
deposit the cost therefor with Landlord.

       (c) If Tenant fails to approve or disapprove the Working Drawings or the
cost of the Excess Improvements, if any, within seventy-two (72) hours, then (i)
Landlord's deadline for Substantial Completion (as hereinafter defined) pursuant
to the Schedule of Responsibilities attached hereto as Exhibit B-2 and made a
part hereof by this reference shall be extended by the number of days or hours
from the time specified in the Schedule of Responsibilities for Tenant's
approval of the Working Drawings and/or the Tenant Costs until the pricing is
finally acceptable to Tenant, and such number of days or hours shall be a Tenant
Delay (as hereinafter defined) and (ii) any redesign costs that may be incurred
as a result of changes requested by Tenant in the Working Drawings outside of
the scope of the Space Plan shall be a Tenant Cost. Upon Tenant's approval of
the Working Drawings and, if there are any Tenant Costs, upon Tenant's payment
of any deposits with Landlord, Landlord's Contractor shall commence construction
of the Tenant Improvements.

       5. SUBSTANTIAL COMPLETION. Landlord's Contractor shall achieve
"Substantial Completion" of the Tenant Improvements in accordance with the Lease
and the Schedule of Responsibilities attached hereto as Exhibit B-2. As used in
this Work Agreement, the Tenant Improvements shall have achieved Substantial
Completion if all of the work called for under the Working Drawings has been
substantially completed in accordance with Landlord's construction

                                      B-2
<PAGE>   43

contract with Landlord's Contractor and Landlord has received the final
inspection authorizing Tenant to take occupancy of the Premises. Substantial
Completion does not include completion of (i) details of construction,
decoration or adjustment which do not substantially interfere with Tenant's
occupancy or the ability of any specialty contractors hired by Tenant to install
fixtures or equipment Tenant has ordered; (ii) any punch list work which does
not affect Tenant's use of the Premises and which can be completed or corrected
as soon as reasonably possible after the Phase I Commencement Date or the Phase
II Commencement Date; (iii) items for which Tenant requests a deferral; and/or
(iv) any long-lead or specialty items required by Tenant. Landlord will give
Tenant no less than ten (10) days' advance written notice of the anticipated
date of Substantial Completion so that Tenant can be prepared to take occupancy
of the Premises on or immediately after the date of Substantial Completion.
Landlord will cooperate with Tenant in allowing Tenant's specialty contractors,
if any, to enter the Premises during said ten-day period to complete work needed
before Tenant will take occupancy.

       6. PUNCH LIST WORK. Prior to delivery of possession of the Premises to
Tenant, Landlord, Tenant, and Landlord's Contractor shall make a final
inspection of the Premises to make certain that the work has been accomplished
according to Working Drawings as amended by any approved changes. A punch list
of items to be completed or corrected shall be prepared as agreed by the
parties, and Landlord's Contractor shall correct such punch list items. If
Tenant, Tenant's agents or employees, and/or any person(s) directly or
indirectly employed by Tenant places furniture, equipment, appliances or any
other items in the Premises and/or any of Tenant's specialty contractors
commence work prior to Landlord's compilation of a punch list regarding any
involved areas of the Premises or the Complex or Common Areas, any damages to
any work in place for which there exists a reasonable doubt as to the party
responsible for such damages shall be deemed to have been caused by Tenant
and/or any persons directly or indirectly employed by Tenant, and Landlord
and/or Landlord's Contractor shall not be held responsible for any costs or
expenses related to or resulting from correction of same.

       7. SCHEDULE OF RESPONSIBILITIES.

          (a) DELAYS. Landlord, Tenant, Landlord's Contractor, and/or any
specialty contractors hired by Tenant shall each strictly abide by all dates set
forth for their respective activities in the Schedule of Responsibilities (the
"Schedule of Responsibilities") attached hereto AS EXHIBIT B-2> and made a part
hereof. Any delay in making such decisions shall be a Tenant Delay. Deadlines
for Landlord's Contractor shall be deemed to be deadlines for Landlord, and any
delays caused by Landlord's Contractor shall be deemed to be delays caused by
Landlord ("Landlord Delays"). Deadlines for Tenant and/or Tenant's specialty
contractors, if any, shall be deemed to be deadlines for Tenant, and any delays
caused by said persons or entities shall be deemed to be delays caused by Tenant
("Tenant Delays"). If Tenant fails to meet any of its deadlines pursuant to the
Schedule of Responsibilities, then each of Landlord's subsequent deadlines shall
be extended by the number of days by which Tenant missed its deadlines. If
Landlord fails to meet any of its deadlines, then each of Tenant's subsequent
deadlines shall be extended by the number of days by which Landlord missed its
deadlines. If Landlord Delays exceed Tenant Delays by more than thirty (30)
days, Landlord shall be liable for the penalty described in Section 7(g) below.

          (b) DECISIONS DURING COURSE OF CONSTRUCTION. Tenant acknowledges that
the construction schedule for Substantial Completion of the Tenant Improvements
will require that Tenant make all decisions about carpet color, paint color, and
other details of design and construction no later than twenty-four (24) hours
after Landlord's Contractor's request for a decision.

                                      B-3

<PAGE>   44

       (c) TENANT'S AGENT. In light of the short schedule under which all
parties involved in construction will be working and the need for immediate
decision-making, Tenant hereby appoints the persons below as Tenant's agents for
purposes of authorizing and executing any and all documents needed to effect
this Work Agreement, and any and all changes, additions or deletions to the work
contemplated herein. Landlord shall have the right to rely on any documents
executed by such authorized persons, and either person is fully authorized to
bind Tenant.

            Asghar D. Mostafa
            10026 Scenic View Terrace
            Vienna, Virginia 22182
            Telephone: (703) 307-2057
            FAX: (703) 759-5303.

       (d) FORCE MAJEURE. All deadlines for all parties hereunder shall be
subject to, and extended by, force majeure which shall mean, but not be limited
to, strikes, lockouts or labor disputes, inability to obtain labor or materials
or reasonable substitutes therefor (other than specialty or long-lead items),
acts of God, enemy or hostile governmental action, civil commotion, abnormally
severe weather conditions preventing construction work in the Premises to
proceed in spite of reasonable efforts, fire or other casualty beyond the
reasonable control of Landlord or Tenant and not due to the fault or negligence
of Landlord, Tenant or the agents, contractors, licensees or employees of either
of them.

       (e) CHANGES. In the event of any changes requested by Tenant to the
Working Drawings, which changes constitute changes to Tenant's previous
instructions specified in the Space Plan, any delays caused by such changes
shall be a Tenant Delay and any redesign costs or costs for additional labor
and/or materials shall be a Tenant Cost. Tenant shall also be fully responsible
as a Tenant Cost for: (i) the costs of any demolition of completed or partially
completed work previously commenced; (ii) the costs, if any, of work in place
and of cancelling any materials ordered and/or received; (iii) the costs of any
redesign required; and (iv) any delays in achieving Substantial Completion of
the work caused by any or all of the above, including any time expended between
the time Landlord's Contractor is told to stop work in a particular area and the
time Landlord's Contractor is then eventually released. Landlord shall not be
required, nor shall Tenant's specialty contractors, if any, be permitted, to
commence work on any such changes until Tenant has approved in writing, the
Tenant Costs (including construction and design) and the time delays
attributable thereto and paid to Landlord the Tenant Costs due. Notwithstanding
the foregoing, Tenant shall have no more than twenty-four (24) hours to approve
the costs and delay attributable to such changes after Tenant's receipt of the
change order therefor. In the event Tenant shall not respond within this time,
Tenant shall be deemed to have approved said costs and delay.

       (f) COMMENCEMENT DATES. The Phase I Commencement Date and the Phase II
Commencement Date shall be the date of Substantial Completion of the Phase I
Space and the Phase II Space, as applicable, minus the total number of days
comprising Tenant Delays plus the total number of days comprising Landlord
Delays. Landlord will build out the Phase II Space without all of the demising
walls at the same time the Phase I Space is built out. If Landlord leases the
Phase II Space to another tenant prior to the Phase II Commencement Date,
Landlord shall deliver the Phase II Space in "as is" condition, broom clean,
provided that the Phase II Space complies with the Working Drawings therefor.

                                       B-4

<PAGE>   45

          (g) LANDLORD DELAY PENALTY. In the event Landlord Delays exceed Tenant
Delays by more than thirty (30) days, for each day of Landlord Delays
thereafter, Landlord shall abate and forgive two (2) days of Base Rent
commencing with the first payment due as of the Phase I Commencement Date or the
Phase II Commencement Date as applicable.

       8. Time of the Essence. Time is of the essence of the obligations of
Landlord and Tenant under this Work Agreement. All days in this Work Agreement
are calendar days.

       9. Miscellaneous.

       (a) Design/Construction/Material Warranties. Tenant acknowledges that
Landlord is not an architect or engineer and that the Tenant Improvements will
be designed and performed by independent architects, engineers and contractors.
Accordingly, Landlord does not guarantee or warrant that the Space Plan or
Working Drawings will be free from errors or omissions nor that the Tenant
Improvements will be free from defects. In the event of such errors, omissions,
or defects, Landlord shall cooperate in any action Tenant desires to bring
against such parties. Landlord shall seek to enforce any warranties it obtains
from any architect, engineer or contractor for the benefit of Tenant. If a
judgment is entered against Landlord for such errors, omissions, or defects of
Landlord's architects, engineers or contractors, Tenant's damages shall be
limited to the cost of reconstructing the Tenant Improvements to correct the
error or omission in the Space Plan or Working Drawings or the defect in the
Tenant Improvements.

       (b) GOVERNMENTAL APPROVALS. Landlord shall, at its cost, apply for the
normal building permits required for the Tenant Improvements described in the
Working Drawings and issued pursuant to the local building code as a ministerial
matter. If the Working Drawings must be revised in order to obtain such building
permits, Landlord shall promptly notify Tenant. Landlord shall promptly have the
Working Drawings revised within seventy-two (72) hours to satisfy the building
permit requirements and shall submit the revised Working Drawings to Tenant for
written approval. Tenant shall provide such written approval within twenty-four
(24) hours. In such event, the Schedule of Responsibilities shall be revised to
reflect a delay in Substantial Completion, but such delay shall be neither a
Landlord Delay nor a Tenant Delay.

       IN WITNESS WHEREOF, Landlord and Tenant have executed this Work Agreement
as of even date with the Lease.

                            TENANT:

WITNESS or ATTEST:          ADVANCED SWITCHING COMMUNICATIONS, INC.,
                            a Delaware corporation

          [SIG]             By:   /s/ ASGHAR D. MOSTAFA            [SEAL]
---------------------------     ------------------------------------
                                Asghar D. Mostafa
                                President and CEO

                            LANDLORD:

WITNESS or ATTEST:          MET LIFE INTERNATIONAL REAL ESTATE EQUITY
                            SHARES, INC.
                            a Delaware corporation

          [SIG]             By:  /s/ T. ANDREW BEHYMER              [SEAL]
---------------------------     ------------------------------------
                                T. Andrew Behymer
                                Vice President

                                      B-5
<PAGE>   46

                                   EXHIBIT B-2
                          SCHEDULE OF RESPONSIBILITIES

<TABLE>
<CAPTION>
                                                                                DATE
<S>                                                                         <C>
1.   Lease executed and delivered                                           September __, 1997

2.   Tenant gives written approval of Working Drawings                      Seventy-two (72)
     (and Tenant Costs, if any) in connection therewith and                 hours after Tenant's
     deposits Tenant Costs with Landlord.                                   receipt of Working Drawings

3.   Tenant's specialty contractors allowed into Premises to                Ten (10) days before
     install fixtures and equipment in Phase I Space.                       date of Substantial Completion

4.   Substantial Completion of Tenant Improvements for the                  December 1, 1997
     Phase I Space
</TABLE>

<PAGE>   47

                                    EXHIBIT C
                        DECLARATION OF COMMENCEMENT DATE

       NOTE: THIS DOCUMENT SHALL BE EXECUTED AFTER EACH OF THE PHASE I
       COMMENCEMENT DATE AND THE PHASE II COMMENCEMENT DATE HAVE BEEN
       DETERMINED.

       THIS DECLARATION OF COMMENCEMENT DATE is made as of the __ day of ______,
199_, by and between MET LIFE INTERNATIONAL REAL ESTATE EQUITY SHARES, INC., a
Delaware corporation ("Landlord"), and ADVANCED SWITCHING COMMUNICATIONS, INC.,
a Delaware corporation ("Tenant").

                                    RECITALS

       A. Landlord and Tenant entered into that certain Deed of Lease (the
"Lease") dated as of September __, 1997, for the lease of certain Premises (as
defined in the Lease) in that certain office building located at 8330 Boone
Blvd., Vienna, Virginia, in the complex known as "American Center".

       B. The Lease provides that after the [PHASE I][PHASE II] Commencement
Date has been determined, Landlord and Tenant shall enter into a written
declaration setting forth the [PHASE I][PHASE II] Commencement Date and the date
upon which the Lease Term (as defined in the Lease) will expire.

       NOW, THEREFORE, in consideration of the mutual promises contained herein
and in the Lease and other good and valuable consideration, the receipt and
sufficiency of which are hereby acknowledged, Landlord and Tenant hereby agree
as follows:

       1. The [PHASE I][PHASE II] Commencement Date is _________, 1999_, and the
Lease Term shall expire on ________, unless terminated earlier or extended in
accordance with the terms of the Lease.

       2. The improvements and space required to be furnished to Tenant under
the terms of the Lease and all other matters required to be furnished or
performed by Landlord have been completed in all respects in accordance with the
terms of the Lease. Tenant acknowledges that Tenant has had an opportunity to
inspect the Premises and accepts the Premises in their condition "as is".

       3. All duties of Landlord of an inducement nature have been fulfilled and
all other obligations required to be performed or observed by Landlord have been
duly and fully performed or observed by Landlord.

       4. Landlord has not waived the performance or observance by Tenant of any
of the terms, covenants, or conditions to be performed or observed by Tenant
under the Lease.

<PAGE>   48
Landlord has made no representations or commitments, oral or written, or
undertaken any obligations other than as may be expressly set forth in the
Lease.

         5. Except as amended by this Declaration, the Lease continues in full
force and effect in accordance with its terms and is enforceable against
Landlord and Tenant in accordance with its terms. No claim, set-off or defense
exists for the benefit of Tenant against Landlord in connection with the Lease,
and to the extent any claims, set-offs or defenses exist, they are hereby waived
and relinquished in their entirety.

         IN WITNESS WHEREOF, Landlord and Tenant have executed this Declaration
of Commencement Date as of the date first above written.

                                LANDLORD:

WITNESS or ATTEST:
                                MET LIFE INTERNATIONAL REAL ESTATE EQUITY
                                SHARES, INC.,
                                  a Delaware corporation

                                By:                                       [SEAL]
-------------------------------     --------------------------------------
                                    Name:
                                    Title:

                                TENANT:

WITNESS or ATTEST:              ADVANCED SWITCHING COMMUNICATIONS, INC.,
                                 a Delaware corporation

                                By:                                       [SEAL]
-------------------------------     -------------------------------------
                                     Asghar D. Mostafa
                                     President and CEO

                                       C-2

<PAGE>   49

                                    EXHIBIT D
                              RULES AND REGULATIONS

1.        Sidewalks, doorways, vestibules, halls, stairways, and similar areas
shall not be obstructed nor shall refuse, furniture, boxes or other items be
placed therein by Tenant or its officers, agents, servants, and employees, or
used for any purpose other than ingress and egress to and from the Premises, or
for going from one part of the Building or Complex to another part of the
Building or Complex. Canvassing, soliciting and peddling in the Complex are
prohibited.

2.        Plumbing fixtures and appliances shall be used only for the purposes
for which constructed, and no unsuitable material shall be placed therein.

3.        No signs, directories, posters, advertisements, or notices shall be
painted or affixed on or to any of the windows or doors, or in corridors or
other Common Areas of the Complex, except in such color, size, and style, and in
such places, as shall be first approved in writing by Landlord in its reasonable
discretion. One building standard suite identification sign will be prepared by
Landlord at Landlord's expense. No additional signs shall be posted without
Landlord's prior written consent as to location and form, and the cost of
preparing and posting such signs shall be borne solely by Tenant. Landlord shall
have the right to remove all unapproved signs without notice to Tenant, at the
expense of Tenant.

4.        Tenants shall not do, or permit anything to be done, in or about the
Complex, or bring or keep anything therein, that will in any way increase the
rate of fire or other insurance on the Complex, or on property kept therein or
otherwise increase the possibility of fire or other casualty.

5.        Landlord shall have the power to prescribe the weight and position of
heavy equipment or objects which may overstress any portion of the floor. All
damage done to the Building by the improper placing of such heavy items will be
repaired at the sole expense of the responsible tenant.

6.        Tenant shall notify the manager of the Complex when safes or other
heavy equipment are to be taken in or out of the Building, and the moving shall
be done after written permission is obtained from Landlord on such conditions as
Landlord shall require. Any moving in or moving out of Tenant equipment,
furniture, files, and/or fixtures shall be done only with prior written notice
to Landlord, and Landlord shall be entitled to prescribe the hours of such
activity, the elevators which shall be available for such activity and shall, in
addition, be entitled to place such other reasonable conditions upon Tenant
moving activities as Landlord deems appropriate. Tenant shall bear all risk of
loss relating to damage incurred with respect to Tenant's property in the
process of such a move, and in addition, shall indemnify and hold Landlord
harmless as to all losses, damages, claims, causes of action, costs and/or
expenses relating to personal injury or property damage sustained by Landlord or
any third party on account of Tenant moving activities.

7.        Corridor doors, when not in use, shall be kept closed.

<PAGE>   50

8.        All deliveries must be made via the service entrance and elevators,
designated by Landlord for service, if any, during Normal Business Hours.
Landlord's written approval must be obtained for any delivery after Normal
Business Hours.

9.        Each tenant shall cooperate with Landlord's employees in keeping its
premises neat and clean.

10.       Tenant shall not cause or permit any improper noises in the Building
or the Complex or allow any unpleasant odors to emanate from the Premises, or
otherwise unreasonably interfere, injure or annoy in any way other tenants or
persons having business with them.

11.       Except for seeing-eye dogs, no animals shall be brought into or kept
in or about the Building or the Complex.

12.       No boxes, crates or other such materials shall be stored in hallways
or other Common Areas. When Tenant must dispose of crates, boxes, or similar
refuse, it will be the responsibility of Tenant to dispose of same prior to 7:30
a.m. or after 6:00 p.m., respectively, so as to avoid having such debris visible
in the Common Areas during Normal Business Hours.

13.       No machinery of any kind, other than ordinary office machines such as
personal computers, calculators, fax machines, and similar standard office
equipment shall be operated in the Premises without the prior written consent of
Landlord, nor shall a tenant use or keep in the Complex any flammable or
explosive fluid or substance (including Christmas trees). No space heaters or
fans shall be operated in the Premises.

14.       No bicycles, motorcycles or similar vehicles will be allowed in the
Complex, except in areas that may be designated by Landlord.

15.       No nails, hooks or screws shall be driven into or inserted in any
part of the Premises except customary picture frames or as otherwise approved by
the manager of the Complex. Nothing shall be affixed to, or made to hang from,
the ceiling of the Premises without Landlord's prior written consent.

16.       Landlord has the right to evacuate the Complex in the event of an
emergency or catastrophe.

17.       No food and/or beverages shall be distributed from Tenant's office
without the prior written approval of the manager of the Complex.

18.       No additional locks shall be placed upon any doors without the prior
written consent of Landlord. All necessary keys shall be furnished by Landlord,
and the same shall be surrendered upon termination of this Lease, and Tenant
shall then give Landlord or his agent an explanation of the combination of all
locks on the doors or vaults. Tenant shall initially be given ten (10)

                                       D-2

<PAGE>   51

keys to the Premises by Landlord. No duplicates of such keys shall be made by
Tenant. Additional keys shall be obtained only from Landlord, at a fee to be
determined by Landlord.

19.       Tenant will not locate furnishings or cabinets adjacent to mechanical
or electrical access panels so as to prevent operating personnel from servicing
such units as routine or emergency access may require. The cost of moving such
furnishings for Landlord's access will be for Tenant's account. The lighting and
air conditioning equipment of the Complex will remain the exclusive charge of
the personnel designated by the manager of the Complex.

20.       Tenant shall comply with parking rules and regulations as may be
posted and distributed from time to time.

21.       No portion of the Complex shall be used for the purpose of lodging
rooms.

22.       Vending machines or dispensing machines of any kind will not be
placed in the Premises by Tenant.

23.       Prior written approval, which shall be at Landlord's sole discretion,
must be obtained for installation of window shades, blinds, drapes, or any other
window treatment of any kind whatsoever. Landlord will control all internal
lighting that may be visible from the exterior of the Complex and shall have
the right to change any unapproved lighting, without notice to Tenant, at
Tenant's expense.

24.       Landlord hereby designates the following days as Normal Business
Holidays (on the dates observed by the federal government), on which days
services will not be provided and normal operating hours will not be followed:

                                 New Year's Day
                     Washington's Birthday (Presidents' Day)
                          Martin Luther King's Birthday
                                  Memorial Day
                                Independence Day
                                    Labor Day
                                  Columbus Day
                                  Veterans Day
                                Thanksgiving Day
                                  Christmas Day

Landlord reserves the right, at its sole option, to designate as a Normal
Business Holiday (i) any other legal public holiday if so promulgated pursuant
to Title 5, Section 6103 of the United States Code or by the Commonwealth of
Virginia; (ii) the Friday after Thanksgiving Day if Landlord reasonably
determines that many occupants of the Complex will be observing that day as a
holiday; and (iii) such other days designated as legal holidays by the
applicable building service union employees' service contract and/or by the
applicable operating engineer's contract.

                                       D-3

<PAGE>   52
25.       No smoking is permitted in the Premises or the Common Areas.

26.       Landlord reserves the right to rescind any of these rules and make
such other and further reasonable rules and regulations as in its reasonable
judgment shall from time to time be needful for the subject to operation of the
Complex subject to the terms of this Lease, which rules shall be binding upon
each Tenant upon delivery to such Tenant of notice thereof in writing.

                                      D-4

<PAGE>   53

                                   EXHIBIT E

                            FORM OF LETTER OF CREDIT

                       IRREVOCABLE LETTER OF CREDIT NO.__

                               September __, 1997

Met Life International Real Estate Equity Shares, Inc.
c/o SSR Realty Advisors, Inc.
Authorized Agent
One North Broadway
Suite 500
White Plains, New York 10601

Gentlemen:

          We hereby establish in favor of Met Life International Real Estate
Equity Shares, Inc. ("Beneficiary"), a Delaware corporation, for the account of
Advanced Switching Communications, Inc., our Irrevocable Letter of Credit in
the amount of ONE MILLION AND NO/100 DOLLARS ($1,000,000.00), effective
immediately and expiring with our close of business on the ________ day of
September, 1998. It is a condition of this Letter of Credit that it will be
automatically extended for additional consecutive periods of one year each from
the present or future expiration date unless you receive from us within sixty
(60) days prior to such date, in writing by registered mail at the above
address, that we elect not to renew this Letter of Credit for such additional
period.

          Funds under this Letter of Credit are available to you against your
sight draft drawn on us, marked thereon "Drawn under Irrevocable Letter of
Credit No. __________" and presented to us at our office at
___________________________, accompanied by your statement addressed to us in
the form attached hereto and incorporated herein as Attachment A.

          We will accept such statement as binding and correct without having
to investigate or having to be responsible for the accuracy, truthfulness, or
validity thereof or any part thereof and notwithstanding the claim of any
person to the contrary.

          We hereby agree with you that the draft drawn in accordance with the
terms and conditions of this Letter of Credit will be honored before the close
of the third banking day following receipt of the aforesaid draft and statement
if presented to us on or before the applicable expiration date in accordance
with the applicable provisions of the Uniform Commercial Code then in effect in
the Commonwealth of Virginia.

          Unless otherwise stated, this Letter of Credit is subject to the
Uniform Customs and Practices for Documentary Credits (1993 Revision),
International Chamber of Commerce Publication No. 500).

                                          Very truly yours,

<PAGE>   54

                                 "ATTACHMENT A"

          Attached to and made a part of Irrevocable Letter of Credit No.
___________ (the "Letter of Credit") dated September __, 1997, issued by
________________, to Met Life International Real Estate Equity Shares, Inc.
("Beneficiary"), a Delaware corporation, for the account of Advanced Switching
Communications, Inc.

          The undersigned, a duly authorized officer of Beneficiary under the
Letter of Credit, certifies and represents that the Beneficiary is drawing on
this Letter of Credit in accordance with the provisions of the Deed of Lease
dated September __,1997, by and between the Beneficiary and Advanced Switching
Communications, Inc.

          The undersigned has executed this statement as of the __ day of
__________________, ______.

WITNESS or ATTEST:                   MET LIFE INTERNATIONAL REAL ESTATE EQUITY
                                     SHARES, INC.
                                     a Delaware corporartion

                                     By:                               [SEAL]
---------------------------             -------------------------------
                                        Name:
                                        Title:

                                      E-2

<PAGE>   55

                  viii) smoke detector

                  ix)  supply plenum w/3 side grilles

                  x)   glycol regulating valve

                  xi)  7/24 temperature and humidity recorder

          b)      Provide dry cooler Liebert model DD-0466 with the following:

                  i)   Dual pump package

                  ii)  Expansion tank

                  iii) Locking disconnect switch

                  iv)  Fan cycling controls

                  v)   460V-3ph

          c)      If existing piping is 3" or greater, it may be used to what
                  extent is feasible. If not feasible, provide 3" type L copper
                  piping with wrought copper fittings. Provide:

          d)      valves and fittings as recommended by the manufacturer at the
                  air conditioning units and dry cooler

          e)      all hangers and supports

9.)       Electrical power shall be reconfigured for the new plan. Typical
          perimeter offices shall have power and data outlets on each of the
          side walls. Additional outlets shall be provided as necessary to
          meet this requirement. The work stations shall require junction boxes
          and, in some locations, core drills providing 4 circuit, 8 wire with
          isolated ground service (4 hots, 2 neutrals, one ground and one
          isolated ground). The Contractors; electrician shall connect the
          Tenant supplied work stations. Electrical requirements in the Network
          Workroom will require upgrades as follows:

          a)      200 Amp., 277/480 Volt, 3 phase, 4 wire feeder from the main
                  electrical room with a sub meter.

          b)      Panel "DP" 225 Amp., 277/480 Volt, 3 phase, 4 wire panelboard
                  with 1-3 Pole 30 Amp. 1-3 Pole 100 Amp and 1-3 Pole 200 Amp
                  breakers

          c)      112.5 KVA Amp and 1-3 Pole 200 Amp breakers 112.5 KVA
                  transformer -- 480 Volt, 3 phase, 3 wire to 120.208 Volt, 3
                  Phase, 4 wire

          d)      Panel "L" -- 400 Amp., 120.208 Volt, 3 Phase 4 wire two
                  section panelboard with 400 Amp main breaker with feed thru
                  lugs:

                        (i)   1st section 42--1 Pole 20 Amp. Breakers.

                        (ii)  2nd section 39--1 Pole 20 Amp. And 1-3 Pole 100
                              Amp. Breakers

          e)      Panel "LA"-- 100 Amp., 120.208 Volt, 3 Phase, 4 wire with
                  14-1 Pole, 20 Amp. And 5-2 Pole 20 Amp. Breakers and isolated
                  ground bus with #6 isolated ground to building service
                  entrance ground.

10.)      Data and communication outlets shall provide a gypsum board trim ring
          and pull string to facilitate cable installation by the Tenant's
          contractor. Provide a plastic grommet in the top runner of the metal
          studs above the ring and string locations.

11.)      Base and wall cabinets in the Coffee stations and the Pantries shall
          be "Avia" by Merillat. Provide plastic laminate on MDF counter tops,
          back and side splash. The ledge below the logo sign shall be plastic
          laminate on MDF scribed to the wall with custom laminate cabinets
          below. The cabinets and counter top in Pantry 2 shall be repaired to
          like new appearance.

12.)      The glass in the two Conference rooms shall be tempered "Herculite"
          style in 4 inch top and bottom polished metal rails with silicon
          vertical joints. The glass into the Network Workroom shall be
          tempered in polish metal top and bottom channels with silicon
          vertical joints and start 3'-6" AFF and extend to the ceiling.

13.)      Provide electric black-out drapes in the Conference rooms on both the
          interior and exterior windows.

<PAGE>   56
14.)      Provide an electrically operating recessed projection screen in both
          Conference rooms similar to Da-Lite Board room Electrol, 70" x 70"
          with High Power viewing surface.

15.)      Provide a data and telephone cable allowance not to exceed $1.25 per
          square foot (no terminations).

16.)      Provide an allowance not to exceed $.50 psf for Reception area
          millwork. (Desk)

17.)      Provide an allowance not to exceed $3,000.00 for Reception area sign.

18.)      Provide two microwave ovens and two full size refrigerators with ice
          makers.

AGREED TO AND ACCEPTED:

TENANT:                                    LANDLORD:
           [SIG]                                      [SIG]
---------------------------                ---------------------------
By    ASGHAR D. MOSTAFA                    By  T. ANDREW BEHYMER

      President & CEO                             Vice President
---------------------------                ---------------------------
Title                                      Title

          9/19/97                                    9/19/97
---------------------------                ---------------------------
Date                                       Date

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