<PAGE>
                                                                   EXHIBIT 10.22

                               SUBLEASE AGREEMENT

     This Sublease Agreement ("Sublease") is made and entered into as of
November 1, 1997, by and between WJLA-TV, a division of Allbritton
Communications Company ("WJLA") and MIL 3, Inc. ("MIL 3").

     WHEREAS, WJLA, as tenant, is a party to that certain Lease Agreement
("Master Lease") dated as of November 3, 1986 (a redacted copy of which is
attached hereto as Exhibit 1) wherein WJLA has leased space from the
International Telecommunications Satellite Organization ("Intelsat") in its
headquarters building ("Building") located at 3007 Tilden Street, NW,
Washington, D.C. 20008; and

     WHEREAS, MIL 3 desires to sublease from WJLA a portion of the space leased
to WJLA under the Master Lease;

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

        1.  Subleased Premises.  MIL 3 hereby subleases from WJLA and WJLA
            ------------------
subleases to MIL 3 for the Sublease Term defined herein a portion of the space
leased by WJLA under the Master Lease consisting of the Sixth (6th) Floor, Pod P
(excluding the link area between Pod P and Pod N) measuring approximately 7,074
rentable square feet as shown on Exhibit 2, attached hereto and incorporated
herein ("Subleased Premises"). MIL 3 shall have access to and occupy the
Subleased Premises. WJLA shall provide janitorial services (including trash
collection) and basic utilities, but shall not provide parking and security
services. Intelsat shall not provide additional parking or services to MIL 3.

        2.  Sublease Term.  The Sublease Term shall commence on November 1, 1997
            -------------
and terminate on October 31, 2002 ("Termination Date"); provided, however, that:
(a) MIL 3 may accelerate the expiration date at any time and without penalty
upon six (6) months' prior written notice to WJLA; and (b) WJLA may accelerate
the expiration date beginning November 1, 1999 without penalty upon six (6)
months' prior written notice to MIL 3 with such expiration date to be effective
no earlier than May 1, 2000.

        3.  Alterations.  MIL 3 will not make or permit anyone to make any
            -----------
alterations, additions or improvements, structural or otherwise (hereinafter
referred to as "Alterations"), in or to the demised premises or the Building,
without the prior written consent of WJLA, which consent shall not be
unreasonably withheld. All Alterations made by MIL 3 shall be at MIL 3's sole
cost and expense, and MIL 3 will indemnify and hold WJLA harmless from and
against any and all liens, claims, or damages which may arise by reason of the
making of any Alterations. Any Alterations approved by WJLA may be left in place
at the expiration of the Sublease. If any Alteration is made without the prior
written consent of WJLA, MIL 3 shall at the expiration of the Sublease, at its
sole cost and expense, remove such Alteration and restore the Sublease Premises
to its original condition, except to the extent that WJLA, in its reasonable
discretion, determines that said Alterations may remain. If MIL 3 fails to
perform such work
<PAGE>

within thirty (30) days after the expiration of the Sublease, WJLA may arrange
to have such Alteration removed at MIL 3's expense.

        4.  Base Rental Rate.  MIL 3's monthly rent shall be the rent WJLA is
            ----------------
currently paying attributed to the Subleased Premises ($14,737.50 based upon an
annual rate of $25 per rentable square foot) which includes operating expenses
and real estate taxes, if any, with such rent payable on the first day of each
month of the Sublease Term. At the beginning of the second lease year (November
1, 1998) and at the beginning of each subsequent lease year of the Sublease, MIL
3's monthly rent shall increase five (5) percent.

        5.  Condition of Subleased Premises.  MIL 3 acknowledges that the
            -------------------------------
Subleased Premises are acceptable on an "as-is" basis with no build-out offset
or rental abatement. WJLA shall provide no other work or services to MIL 3
through the Sublease Term except as provided in this Sublease.

        6.  Access.  MIL 3 shall have access to the Building and Sublease
            ------
Premises twenty-four (24) hours a day, seven (7) days a week, 365 days per year.

        7.  Building Services.  WJLA, through the Master Lease, represents that
            -----------------
Intelsat will maintain heating, ventilation and air conditioning services as
provided in the Master Lease. WJLA shall maintain the supplemental HVAC
equipment installed in the Subleased Premises.

        8.  Security Deposit.  MIL 3 shall deliver to WJLA simultaneously with
            ----------------
the execution hereof the sum of $14,737.50 ("Security Deposit"). WJLA, as soon
as practicable thereafter, shall deposit the Security Deposit in a separate
federally insured interest-bearing savings account with interest credited to MIL
3. Provided MIL 3 has complied with all the terms and conditions of this
Sublease and no MIL 3 Event of Default has then occurred or is occurring, WJLA
shall return the Security Deposit fifteen (15) days following the later of the
last day of the Sublease or the date on which the work required by Section 3 is
completed, if any.

        9.  Insurance.  MIL 3 shall obtain and maintain in effect at all times
            ---------
during the term of this Sublease a policy of comprehensive public liability
insurance, naming WJLA and Intelsat as additional insureds, protecting MIL 3,
WJLA and Intelsat against any liability for bodily injury, death or property
damage occurring upon, in or about any part of the Subleased Premises arising
from any of the items set forth in this Paragraph against which MIL 3 is
required to indemnify WJLA, with such policies to afford protection (1) with
respect to bodily injury or death to the limit of not less than One Million
Dollars ($1,000,000) to any one person and to the limit of not less than Three
Million Dollars ($3,000,000) with respect to any one accident, and (ii) with
respect to damage to the property of any one owner to the limit of not less than
Five Hundred Thousand Dollars ($500,000). Such insurance policies shall be
issued by responsible insurance companies licensed to do business in the
District of Columbia. A certificate of insurance evidencing the issuance of such
insurance policy, together with evidence of payment of premiums thereon, shall
be delivered to WJLA upon WJLA's written request prior to the Commencement Date
and at least thirty (30) days before the expiration date of any policy evidenced
by a certificate previously furnished.

                                      -2-
<PAGE>

        10.  Damages.  MIL 3 shall be responsible for any and all damages which
             -------
occur in the Sublease Premises except to the extent they result from acts of God
or any actions taken by Intelsat or WJLA or any other tenant of the Building.
MIL 3 shall, on the Termination Date, at its own expense, remove all signs and
advertising devices and repair any damage caused by such removal.

        11.  Representations and Warranties of WJLA.  WJLA represents and
             --------------------------------------
warrants to MIL 3 that: (A) the Master Lease is valid and existing, in full
force and effect and Exhibit 1 contains a true and correct copy of the Master
Lease as amended to date (exclusive of confidential information and economic
terms and conditions) and there are no other agreements with Intelsat with
respect to the Sublease Premises; (B) there are no existing defaults on the part
of Intelsat or WJLA with respect to the Master Lease; (C) Intelsat does not hold
any claim against WJIA; and (D) there are and will be no contracts for service
or otherwise which expressly or impliedly are or will be binding upon MIL 3 or
the Sublease Premises.

        12.  Representations, Warranties and Covenants of MIL 3.
             --------------------------------------------------

        12.1.  Representations, Warranties.  MIL 3 acknowledges that MIL 3 has
               ---------------------------
received a copy of the Master Lease (with certain provisions thereof redacted by
WJLA) and agrees that this Sublease is subject to all of the terms and
conditions of the Master Lease, except as specifically redacted exempted or
modified herein.

        12.2.  Covenants.  MIL 3 covenants and agrees to: (A) indemnify and hold
               ---------
harmless WJLA from MIL 3s failure to comply with the terms and conditions of the
Master Lease or this Sublease; (B) permit Intelsat and WJLA (and their agents or
representatives), who will use reasonable, good faith efforts to minimize
disruption to MIL 3's business, upon proper notice, except no prior notice is
required in the event of an emergency to enter and inspect the Sublease Premises
during normal business hours to verify MIL 3's compliance with the Sublease; (C)
furnish WJLA with copies of all renewals of insurance and all other obligations
relating to Master Lease and/or consent obligations; (D) inform WJLA in writing
of all material contacts with Intelsat and send WJLA copies of all material
correspondence with Intelsat; (E) permit WJLA to participate in any meetings
with Intelsat concerning the Master Lease; (F) subject to the provisions of
Paragraph 3, return the Sublease Premises to WRA on the Termination Date in the
condition received, reasonable wear and tear excepted. MIL 3 shall not commit or
permit to be committed on the Sublease Premises any act or omission which shall
violate any term or condition of the Master Lease or assign or sublease the
Sublease Premises except as otherwise provided for in this Sublease.

        13.  Master Lease; Consent.
             ---------------------

        13.1.  Incorporation by Reference; Conflicts. Capitalized terms used in
               -------------------------------------
this Sublease, and not otherwise defined are used with the meaning given such
terms in the Master Lease. Except as otherwise provided in this Sublease, all of
the covenants, agreements, terms, provisions and conditions of the Master Lease
insofar as they relate to the Sublease Premises are incorporated herein and made
a part of hereof. Except where otherwise specifically provided in this Sublease,
the obligations of WJLA as tenant under the Master Lease shall be binding upon
MIL 3 during the Sublease Term, but only with respect to the Sublease Premises,
with the same

                                      -3-
<PAGE>

force and effect as if herein set forth at length and with respect thereto the
words "Landlord" and "Tenant" as used in the Master Lease, shall be deemed to
refer to WJLA and MIL 3 respectively. In the event of a conflict between this
Sublease and the Master Lease, the Master Lease shall prevail.

        13.2.  Liability and Indemnity.  WJLA shall not be liable with respect
               -----------------------
to the Sublease Premises under the Master Lease or this Sublease for any breach,
defaults, negligence or willful omissions by Intelsat, its agents, successors or
assigns, but shall be liable only for its own acts, negligence or willful
omissions, or those of its agents, successors or assigns, and shall indemnify
and save harmless MIL 3 from same. MIL 3 shall indemnify and save harmless WJLA
and Intelsat with respect to personal injury, death or property damage in the
Sublease Premises and from any failure to comply with this Sublease and the
Master Lease to the same extent as WJIA has agreed to indemnify Intelsat under
the terms of the Master Lease.

        14.  Confidentiality.  MIL 3 shall keep and maintain the confidentiality
             ---------------
of this Sublease and all information contained in the Master Lease, and shall
use it only for such purposes and in the manner previously agreed to in writing
by WJLA. Specifically, this Sublease and the Master Lease along with all terms
thereof and hereof shall be considered proprietary information of WJLA and
Intelsat, and shall not be given or disclosed to any person, firm or entity
(other than employees of MIL 3 on a "need to know" basis), and in no event shall
such proprietary information be given or disclosed to any real estate broker or
any other tenant or prospective tenant in the Building.

        15.  Event of Default; Remedies.
             --------------------------

        15.1.  Event of Default.  An "Event of Default" shall occur: (A) upon
               ----------------
the occurrence of an event of default described in the Master Lease, (each
reference to Landlord and Tenant to be deemed to refer to WJIA and MIL 3); (B)
in the event any representation or warranty which either party has made or makes
in this Sublease proves to be false or erroneous in any material way; or (C) in
the event that either party breaches or fails to observe or fails to perform any
term or covenant provided for in this Sublease and such breach or failure has
not been cured within ten (10) days after receiving written notice from the
other party of such breach or failure.

        15.2.  Remedies.  Upon the occurrence of an Event of Default, in
               --------
addition to any other rights and remedies either party may have under the
Sublease or at law or in equity, the other party shall have the rights and
remedies as set forth in this Sublease and the Master Lease.

        16.  Miscellaneous.
             -------------

        16.1.  Waivers.  The failure at any time of either party to require
               -------
performance of any obligation provided for in this Sublease shall in no way
affect the right to require such performance at any time thereafter, nor shall
the waiver of any breach constitute a waiver of any succeeding breach of the
same or any other such provision or constitute a waiver of the responsibility of
obligation itself.

        16.2.  Assignment: Subleasing.  MIL 3 shall not sublease, assign,
               ----------------------
mortgage, transfer or otherwise encumber this Sublease without the prior written
consent(s) of Intelsat, if

                                      -4-
<PAGE>

necessary, and WJLA, which consent, in the case of WJLA, shall not be
unreasonably withheld, conditioned or delayed. This Sublease shall be binding
upon and inure to the benefit of the parties named herein and the respective
successors and permitted assigns; provided, however, that any assignment of this
Sublease by WJLA or MIL 3 shall require the prior written consent of the other
except with respect to assignments to any entity controlling, controlled by or
under common control with the assigning party.

        16.3.  Notices.  All notices, requests, demands, communications or
               -------
information which are required to be or may be given under or in connection with
this Sublease shall be in writing and shall be deemed given when delivered
personally or by facsimile copy (with transmission confirmed), or upon receipt
(or in the date rejected or returned if not accepted) after dispatch by
certified or registered first class mail, postage prepaid, return receipt
requested, or a well-recognized overnight courier, directed to the party to whom
the same is so given or made at the address or facsimile number of such party as
hereinafter set forth or such other address or facsimile number as the parties
may hereinafter designate:

If to WJLA:               3007 Tilden Street, NW
                          Washington, D.C. 20006
                          Attn: General Manager
                          Fax: 202-364-1943

With copies to:           Allbritton Communications Company
                          808 17th Street, NW
                          Suite 300
                          Washington, D.C. 20008
                          Attn: General Counsel
                          Fax: 202-331-1898

If to MIL 3:              MIL 3, Inc.
                          3400 International Drive NW
                          Washington, D.C. 20008
                          Attn: Marc Cohen
                          Fax: 202-364-8554

        16.4.  Headings.  The headings of the sections of this Sublease are
               --------
inserted for convenience of reference only and shall not be deemed to constitute
a part hereof.

        16.5.  Entire Agreement; Amendments; Precedence.  This Sublease and
               ----------------------------------------
appended Exhibits contain the entire agreement between the parties hereto, and
supersede all previous agreements, negotiations and discussions between the
parties hereto. Any agreement made hereafter shall not operate to modify,
change, terminate or discharge this Sublease in whole or in part unless such an
agreement is in writing and is signed by both WJLA and MIL 3 and Intelsat, if
required.

        16.6.  Severability.  If any part of, or any provision of this Sublease
               ------------
or any other agreement, document or writing given pursuant to or in connection
with this Sublease shall be deemed to be invalid or unenforceable in any
respect, such part shall be ineffective to the extent

                                      -5-
<PAGE>

of such invalidity only and stricken as though never written, without in any way
affecting the remaining parts of such provisions or the remaining provisions of
this Sublease, provided that the removal of the unenforceable provision(s) does
not materially alter the benefits of the Sublease for either party.

        16.7.  Expenses; Brokers and Agents.  WJLA and MIL 3 shall each bear its
               ----------------------------
own expenses and costs, including, but not limited to, attorneys' fees and
expenses. Both parties represent and warrant to each other that no brokers have
been used regarding this Sublease. WHA shall indemnify and hold MIL 3 harmless,
and MIL 3 shall indemnify and hold WJLA harmless, from and against any claim or
claims of brokerage or other commission arising from or out of any breach of the
foregoing representation and warranty by the respective indemnitors.

        16.8.  Counterparts.  This Sublease may be executed in two counterparts,
               ------------
each of which, when executed, shall be deemed an original and all of which
together shall be deemed one and the same instrument.

        16.9.  Governing Law.  This Sublease, its validity and all rights,
               -------------
obligations, liabilities and responsibilities of the parties hereto, shall be
governed and interpreted in accordance with the laws of the District of Columbia
without giving effect to the principles of conflict of laws thereof.

                                      -6-
<PAGE>

     IN WITNESS WHEREOF, the undersigned have executed this Sublease as of the
date first noted above.

                                             WJLA-TV, a Division of Allbritton
                                             Communications Company:

Witness/Attest

  [sig]                                      By:   /s/ Terrence J. Connelly
--------------------------------------           ------------------------------
                                             Terrence J. Connelly
                                             President and General Manager


                                             MIL 3, Inc.

Witness/Attest

  /s/ Carrie L. Bell                         By:    /s/ Marc A. Cohen
--------------------------------------           ------------------------------
                                             Marc A. Cohen
                                             CEO


                                      -7-
<PAGE>

In the City of Washington  )(S)
District of Columbia       )(S)

I, Barbara A. Wylie, Notary Public in and for the District of Columbia, do
hereby certify that Terrence J. Connelly, who is named as the President of WJLA
in the foregoing and attached Sublease bearing the date of November 1, 1997,
personally appeared before me in said District of Columbia, the said Terrence J.
Connelly being personally known to me as the person named in said Sublease, and
acknowledged the Sublease to be the act and deed of WJLA-TV, a division of
Allbritton Communications Company and that he delivered the same as such for the
purposes stated therein.

     Given my hand and seal this 7 day of January, 1998.

                                    /s/ Barbara A. Wylie
                                  ----------------------
                                  Notary Public

My Commission Expires:

Barbara A. Wylie
Notary Public
District of Columbia
Commission Expires:  August 31, 1998

                                      -8-
<PAGE>

In the City of Washington  )(S)
District of Columbia       )(S)

I, Alma L. Fagan, Notary Public in and for the District of Columbia, do hereby
certify that Marc A. Cohen, who is named as the CEO of MIL 3 in the foregoing
and attached Sublease bearing the date of November 1, 1997, personally appeared
before me in said District of Columbia, being personally known to me as the
person named in said Sublease, and acknowledged the Sublease to be the act and
deed of MIL 3, Inc., a division of Allbritton Communications Company and that he
delivered the same as such for the purposes stated therein.

     Given my hand and seal this 7th day of January, 1998.

                                    /s/ Alma L. Fagan
                                  -------------------
                                  Notary Public

My Commission Expires:    7/31/02
                         ------------

                                      -9-
<PAGE>

                            OFFICE LEASE AGREEMENT
                            ----------------------

     THIS LEASE, dated as of the date specified in the Basic Lease Information,
is made between Landlord and Tenant.

                                   ARTICLE 1

                                   PREMISES

        Section 1.01.  Landlord leases to Tenant, and Tenant leases from
        -------------
Landlord, for the Term (as defined below) and subject to the provisions hereof,
to each of which Landlord and Tenant mutually agree, the Premises, together with
the right to use, in common with others, subject to such reason-able security
regulations as may be imposed by Landlord from time to time, the lobbies,
entrances, stairs, elevators, off-street loading areas (for loading and
unloading of materials and supplies) and other public portions of the Building,
which Building has been and is being constructed on the real property described
in Exhibit B hereto (the "Land"). For purposes of this lease, the term
"Building" means the office towers in which the Premises will be located, as
well as the concourses, lobbies, plazas, walkways, open spaces, landscaped
areas, and similar public areas located on, above, beneath, or immediately
adjacent to the Land, and any truck accessways, loading docks, or similar
facilities, if any, which serve the office towers. While such facilities are not
a portion of the Premises hereunder, Landlord agrees that Tenant shall be
permitted a single Pod connection for access to and the right to use, and to
have officers, employees, contractors and invitees of Tenant use, the loading
dock facilities and the cafeteria all located within the INTELSAT Headquarters
Building during the Term of this lease and any extension hereof, at no
additional charge to Tenant or its officers, employees or invitees other than
payment at prevailing charges imposed on other users for food, beverages and
services provided at the cafeteria plus any additional sales tax which may be
applicable, it being understood and agreed that there will only be one
connection at a single location between the Building and the remainder of the
INTELSAT Headquarters Building.

                (a)  The Rentable Area of the Premises is approximately as
stated in the Basic Lease Information and shall be specifically calculated by
Landlord's architect when floor plans are complete, in accordance with Exhibit E
attached hereto. Upon such determination by Landlord's architect, the Rentable
Area of the Premises and the Annual Rental as those terms are defined in this
lease, shall be appropriately adjusted to reflect the number of square feet of
Rentable Area of the Premises as determined by such calculation. In the event of
any future increase or decrease in the size of the Premises (by reason of the
exercise by Tenant of its expansion option pursuant to Article 33 or otherwise),
Tenant's Proportionate Share shall be appropriately adjusted. Promptly after
Landlord's architect has calculated the Rentable Area of the Premises, Landlord
will give Tenant written notice of the Rentable Area of the Premises thus
calculated. In the event that Tenant disagrees with such calculation based on a
calculation performed by its architect and gives written notice to Landlord of
such disagreement within thirty (30) days after receipt of such notice
containing the calculation provided by Landlord's architect, the Rentable Area
of the Premises shall be determined in the following manner. If the Rentable
Area of the Premises as calculated by Landlord's architect is within one hundred
(100) square feet of the Rentable Area of the Premises as calculated by Tenant's
architect, then the Rentable Area of the Premises for purposes hereof shall
equal the average of the two
<PAGE>

calculations. In the event the two calculations are not within one hundred (100)
square feet, Landlord's architect and Tenant's architect shall mutually agree
upon a third licensed, qualified and independent architect. In the event
Landlord's architect and Tenant's architect are not able to agree on a third
architect within fifteen (15) days after Landlord and Tenant are notified of the
determination of the architects, either party may request that the President of
the Washington Board of Realtors appoint the third architect. The third
architect shall calculate the Rentable Area of the Premises in accordance with
Exhibit E, and such calculation will be final and binding upon both Tenant and
Landlord. Landlord and Tenant shall each bear the cost of their respective
architects, and the cost of the third architect shall be borne equally between
Landlord and Tenant.

                (b)  The Rentable Area of the Building shall be calculated by
Landlord's architect when the Base Building Work (as defined in Exhibit C) is
complete, in accordance with Exhibit E attached hereto, with the Rentable Area
of each floor of the Building to be calculated for purposes hereof as if such
floor were a single tenancy floor. Landlord will give Tenant written notice of
the Rentable Area of the Building thus calculated by its architect. In the event
that Tenant disagrees with such calculation based on a calculation performed by
its architect and gives written notice to Landlord of such disagreement within
thirty (30) days after receipt of such notice containing the calculation
provided by Landlord's architect, the Rentable Area of the Building shall be
determined in the following manner. If the Rentable Area of the Building as
calculated by Landlord's architect is within two hundred (200) square feet of
the Rentable Area of the Building as calculated by Tenant's architect, then the
Rentable Area of the Building for purposes hereof shall equal the average of the
two calculations. In the event the two calculations are not within two hundred
(200) square feet, Landlord's architect and Tenant's architect shall mutually
agree upon a third licensed, qualified and independent architect. In the event
Landlord's architect and Tenant's architect are not able to agree on a third
architect within fifteen (15) days after Landlord and Tenant are notified of the
determination of the architects, either party may request that the President of
the Washington Board of Realtors appoint the third architect. The third
architect shall calculate the Rentable Area of the Building in accordance with
Exhibit E, and such calculation will be final and binding upon both Tenant and
Landlord. Landlord and Tenant shall each bear the cost of their respective
architects, and the cost of the third architect shall be borne equally between
Landlord and Tenant.

                (c)  Tenant's Proportionate Share shall be the percentage
equivalent of a fraction having as its numerator the Rentable Area of the
Premises determined under Section 1.02(a) and having as its denominator the
Rentable Area of the Building determined under Section 1.02(b). In the event of
any future increase or decrease in the size of the Premises (by reason of the
exercise by Tenant of its expansion option pursuant to Article 33 or otherwise),
Tenant's Proportionate Share shall be appropriately adjusted.

                (d)  The Rentable Area of the Premises and Rentable Area of the
Building determined pursuant to this Section 1.02 shall be used as the basis for
the computation of all items of Rental and the computation of Tenant's
Proportionate Share. At the request of either party, the parties shall, from
time to time, execute instruments confirming the Rentable Area of the Premises,
the Rentable Area of the Building, and the Tenant's Proportionate Share.

                                      -2-
<PAGE>

                                   ARTICLE 2

                                     TERM

        Section 2.01.  (a) The term of this lease (the "Term") shall begin on a
        -------------
date (the "Commencement Date") which is the earlier of: (i) the date of Tenant's
occupancy of the Premises for the conduct of its normal business operations,
(ii) seven and one-half (7 1/2) months after the date on which construction of
the Base Building Work (as defined in Exhibit C) is substantially completed or
(iii) fifteen (15) days after (a) Tenant Build-out as described in Exhibit C has
been substantially completed and (b) the Communication Systems described in
Exhibit K have been installed on the Building and Land, so as to permit Tenant
to occupy the Premises and conduct its normal business operations therein, it
being stipulated that Tenant agrees, subject to delay by force majeure as
defined in Section 2.01(b), to exercise reasonable diligence to complete and
install such Tenant Build-out and Communication Systems after Tenant is afforded
access to the Land, Building and Premises for such purpose. Unless sooner
terminated, the Term shall end at midnight on the Expiration Date. Landlord
shall deliver to Tenant at least fifteen (15) days' prior written notice of the
date of substantial completion of the Base Building Work.

                (b)  As used herein, the term "force majeure" means a lockout,
strike or other labor or industrial circumstance (whether on the part of
employees of Landlord or Tenant), civil disturbance, future order of any
government, court or regulatory body claiming jurisdiction, act of the public
enemy, riot, sabotage, blockage, embargo, failure or inability to obtain, or
delay in obtaining materials, supplies or labor through ordinary sources by
reason of short-ages or priority or regulation or order of any government or
regulatory authority or other cause beyond the reasonable control of Landlord or
Tenant, lightning, earthquake, fire, storm, hurricane, flood, washout,
explosion, Act of God, failure or refusal by the Landlord or Tenant, as the case
may be, to perform or observe its agreements or undertakings hereunder, or any
cause whatsoever beyond the reasonable control of Landlord or Tenant, as the
case may be, or its contractors, or other representatives, whether or not
similar to any of the causes hereinabove enumerated; provided, however, that for
purposes of this definition lack of funds by Landlord or Tenant shall not be
deemed to be a cause beyond the control of Landlord or Tenant, as the case may
be, and a force majeure circumstance shall be deemed to exist only so long as
Landlord or Tenant promptly notifies the other in writing thereof specifying the
particulars and is exercising due diligence to remove or overcome such force
majeure circumstance (except that nothing contained in this definition of force
majeure or elsewhere in this lease shall require or obligate Landlord or Tenant
to settle a strike or other labor dispute when it does not wish to do so).

        Section 2.02.    Provided Tenant performs all of Tenant's obligations
        -------------
under this lease, including the payment of Rental (as defined below), Tenant
shall, during the Term, enjoy the Premises without disturbance from Landlord or
any other persons claiming or acting by, through, or under Landlord; subject,
however, to the terms of this lease. This covenant and all other covenants of
Landlord now or hereafter in this lease shall be binding upon Landlord and its
successors only with respect to breaches based on Landlord's acts or omissions
occurring during its and their respective ownership of Landlord's interest
hereunder (including Landlord's right, title and interest in and to the Ground
Lease described in Section 25.01 and any buildings and improvements on the land
described therein).

                                      -3-
<PAGE>

        Section 2.03.    Landlord shall notify Tenant of the date determined to
        -------------
be the Commencement Date pursuant to Section 2.01 and, within fifteen (15) days
after delivery of such notice, Landlord and Tenant shall execute a written
instrument substantially in the form of Exhibit D attached hereto confirming
such date as the Commencement Date; provided that if Tenant in good faith
disagrees with Landlord as to the Commencement Date thus determined by Landlord,
such instrument specifying the actual Commencement Date shall not be executed
until resolution of such dispute by agreement of Tenant and Landlord or by final
judgment of a court of competent jurisdiction not subject to further appeal. Any
failure of the parties to execute such written instrument shall not affect the
validity of the Commencement Date as determined as aforesaid.

                                   ARTICLE 3

                      DELIVERY OF THE PREMISES TO TENANT

        Section 3.01.    Landlord will endeavor to substantially complete the
        -------------
floor(s) in which the Premises are located and to construct and install in the
Premises the Base Building Work (as defined in Exhibit C hereof) seven and one-
half (7-1/2) months prior to the Target Commencement Date specified in the Basic
Lease Information. If for any reason Landlord cannot deliver the Premises to
Tenant by such date, this lease shall not be void or voidable, nor shall
Landlord be liable for any loss or damage resulting therefrom. Notwithstanding
the foregoing, in the event Landlord has not substantially completed the Base
Building Work by April 1, 1989, which date shall be extended by the number of
days of Tenant delay as described in Article 6 and 7 of Exhibit C, Landlord
shall be liable to Tenant for the amount by which (i) Tenant's rent expenses in
its present space, or substitute space, as the case may be, exceed (ii) the
Rental Tenant would reasonably be obligated to pay Landlord hereunder had Tenant
been occupying the Premises (without regard to any free rent period), which
excess shall be computed for the period commencing on April 1, 1989 (as extended
aforesaid by Tenant delays) and ending on the earlier of April 1, 1990 or the
date on which Landlord, at Landlord's option sends written notice to Tenant
giving Tenant the right to terminate this lease by reason of the non-completion
of the Base Building Work. In the event Landlord has not substantially completed
the Base Building Work by April 1, 1990, which date shall be extended by the
number of days of Tenant delays as described in Article 6 and 7 of Exhibit C,
or, in the event Landlord has given Tenant the right, exercisable at any time
prior to the date on which the Base Building Work is substantially completed, to
terminate the lease pursuant to the preceding sentence, Tenant shall have the
right to terminate this lease by giving Landlord written notice of such
election, in which event neither Landlord nor Tenant shall have any further
liability or responsibility hereunder or in connection herewith; provided that
Tenant may promptly remove any property of Tenant which Tenant had placed or
installed in or on the Premises, Building or Land (and repair any damage caused
by such removal) and shall be entitled to receive a refund from Landlord of the
monthly installment of Annual Rental paid by Tenant incident to the execution of
this lease. Tenant may not, without Landlord's consent, enter or occupy the
Premises, Building or Land until the Base Building Work is substantially
completed. However, Landlord agrees that it will permit Tenant and its
contractors to have access to the Premises, Building or Land, or portions
thereof as applicable as promptly as practicable to commence construction and
installation of Tenant Build-out and Communication Systems prior tot the
substantial completion of the Base Building Work if and to the extent Landlord
determines in good faith that such work by Tenant

                                      -4-
<PAGE>

or its contractors will not unreasonably interfere with the work of Landlord and
its contractors in completing the Building and Base Building Work.

        Section 3.02.    The scheduling and coordination of Tenant's contractors
        -------------
and their workers and mechanics will be subject to reasonable regulation by
Landlord or Landlord's contractor to avoid interferences with labor employed by
Landlord, Landlord's contractor or their mechanics or subcontractors and their
workers or mechanics. The foregoing license to enter prior to the Commencement
Date, however, is conditioned upon Tenant's workers and mechanics working in
harmony and not unreasonably interfering with the labor employed by Landlord,
Landlord's mechanics or contractors or by any other tenant or its contractors.
Any such entry before the Commencement Date shall be subject to all terms of
this lease, except the covenant to pay Rental. Landlord shall not be responsible
for any loss or damage to the Tenant Build-out.

        Section 3.03.    The terms of Exhibit C hereto shall govern the
        -------------
construction and-installation of Tenant Build-out.

                                   ARTICLE 4

                          ACCEPTANCE OF THE PREMISES
                            AND BUILDING BY TENANT

     Taking possession of the Premises by Tenant and commencement of its normal
business operations therein shall be conclusive evidence that Tenant: (a)
accepts the Premises as suitable for the purposes for which they are leased (b)
accepts the Building and every part and appurtenance thereof) as being in a good
and satisfactory condition; and (c) waives any defects in the Premises or the
Building except for the completion of those items, if any, on Landlord's punch
list, and latent defects, and except for the completion or correction of those
items, if any, which shall be specified by written notice given by Tenant to
Landlord within thirty (30) days after Tenant has taken possession of the
Premises and commenced its normal business operations therein.  Landlord shall
not be liable, except for gross negligence or willful misconduct, to Tenant or
any of its agents, employees, licensees, servants, or invitees for any injury or
damage to person or property due to the condition or design of or any defect in
the Building or its mechanical systems and equipment which may exist or occur,
and Tenant, for itself and its agents, employees, licensees, servants, and
invitees, expressly assumes all risks of injury or damage to person or property,
either proximate or remote, resulting from the condition of the Premises or the
Building.

                                   ARTICLE 5

                                    RENTAL

        Section 5.01.    Subject to the last sentence of this Section 5.01,
        -------------
commencing on the Commencement Date, Tenant shall Day to Landlord monthly, in
advance, without demand, on the first day of each calendar month during each
Lease Year, an annual rental ("Annual Rental") in an amount equal to 1/12 of the
Annual Rental specified in the Basic Lease Information, subject to adjustment as
provided in Section 1.02, and Article 32 hereof. [redacted text] shall be

                                      -5-
<PAGE>

payable in advance by Tenant on the date of execution of this lease.  If the
Commencement Date is a date other than the first day of a calendar month, then
the monthly installment of Rental for the first month for which rent is owing,
being a fractional month, shall be appropriately prorated.  If the Expiration
Date is a date other than the last day of a calendar month, then the monthly
installment of Rental for the last month for which rent is owing, being a
fractional month, shall be appropriately prorated.  Landlord hereby waives and
abates payment of the Annual Rental for the first seven (7) months of the Term.

        Section 5.02.    All Rental shall be paid to Landlord by Tenant when
        -------------
due, without deduction, offset or counter-claims, in lawful money of the United
States, at Landlord's Address for Notices as specified in the Basic Lease
Information, or such other place as Landlord may from time to time designate.
The term "Rental" as used herein means the then applicable Annual Rental,
Tenant's Proportionate Share of Basic Costs Excess (as hereinafter defined), and
all other sums payable by Tenant under this lease. All past due installments of
Rental shall bear interest from the date due until paid at a rate per annum
equal to [redacted text] above the prime or base rate (the "Prime Rate")
publicly announced by The Riggs National Bank of Washington, D.C. (or its
successor), from time to time; provided, however, that any interest payable
pursuant to this Section 5.03 shall never exceed the Highest Lawful Rate. The
term "Highest Lawful Rate" as used herein shall mean the maximum rate of
interest from time to time permitted to be charged under applicable law to
Tenant with respect to the indebtedness for which such interest is charged under
this lease.

        Section 5.03.    It is agreed by Landlord and Tenant that no Rental for
        -------------
the use, occupancy or utilization of the Premises shall be, or is, based in
whole or in part on the net income of profits derived by any person from the
Building or the Premises, and the Tenant further agrees that it will not enter
into any sublease, license, concession or other agreement for any use, occupancy
or utilization of the Premises which provides for a rental or other payment for
such use, occupancy or utilization based in whole or in part on the net income
or profits derived by any person from the Premises so leased, used, occupied or
utilized. Nothing in the foregoing sentence, however, shall be construed as
permitting or constituting Landlord's approval of any sublease, license,
concession, or other use, occupancy, or utilization agreement not otherwise
approved by Landlord in accordance with the provisions of Article 18 hereof.

                                   ARTICLE 6

                                OPERATING COSTS

        Section 6.01.    Throughout the Term, beginning with the Fiscal Year
        -------------
following the Fiscal Year in which the Commencement Date occurs, Tenant shall
pay Tenant's Proportionate Share of the amount ("Basic Costs Excess") by which
Basic Costs for such Fiscal Year exceed the Basic Costs Base Amount. Such
payments of Tenant's Proportionate Share of Basic Costs Excess shall be made as
follows:

                (a)  Before the beginning of each Fiscal Year during the Term,
commencing with the first Fiscal Year after the Fiscal Year in which the
Commencement Date occurs, Land-lord shall furnish Tenant with Landlord's
estimate of the Basic Costs Excess for such Fiscal Year. Subject to subparagraph
(b)(v) of this Section 6.01, by the first day of each month during

                                      -6-
<PAGE>

such Fiscal Year, Tenant shall pay 1/12th of its Proportionate Share of the
estimated Basic Costs Excess for such Fiscal Year.

                (b)  (i)  Within the first one hundred twenty (120) days of each
Fiscal Year during the Term (beginning with the second Fiscal Year following
calendar year 1988), and within one hundred twenty (120) days after the end of
the Fiscal Year during which the Expiration Date occurs, or as soon thereafter
as reasonably practical, Landlord shall furnish to Tenant a statement ("Expense
Statement") of the actual Basic Costs for the previous Fiscal Year, certified to
be true and accurate by Landlord to its knowledge and belief.

                     (ii) Within thirty (30) days after the delivery of the
Expense Statement, a lump sum payment will be made by Tenant equal to the
amount, if any, by which Tenant's Proportionate Share of the actual Basic Costs
exceeds the amount, if any, which Tenant has paid toward the estimated Basic
Cost Excess for such previous Fiscal Year.

                     (iii)  If Tenant's Proportionate Share of the actual Basic
Costs is less than the amount Tenant has paid toward the estimated Basic Costs
Excess for such previous Fiscal Year, Landlord shall refund the excess to Tenant
within thirty (30) days after the issuance of the Expense Statement or, at
Landlord's option, Landlord shall apply such amount to the next payments of
Rental due hereunder.

                     (iv) The effect of the reconciliation payment or adjustment
pursuant to (ii) or (iii) above is that Tenant shall pay during each Fiscal Year
during the Term its Proportionate Share of the Basic Costs Excess.

                     (v)  Notwithstanding anything herein contained to the
contrary, Landlord hereby waives and abates payment by Tenant of Tenant's
Proportionate Share of Basic Costs Excess for the period ending at the
expiration of twelve (12) full calendar months after the Commencement Date.

                     (vi) In the event that Tenant pays to Landlord Landlord's
determination of the amount due pursuant to subparagraph (b)(ii) of this Section
6.01, and included with such payment is a notice advising Landlord that Tenant
disputes the amount Landlord claims is owing together with the reasons for such
dispute in reasonable detail, then in the event that it is ultimately determined
that Tenant's payment exceeded the amount which should have been due, Tenant
shall be entitled to interest at the Prime Rate plus one percent (1%) per annum
on the amount of the overpayment from the date paid until the Landlord remits to
Tenant the amount of the overpayment.

                (c)  Within thirty (30) days after delivery of an Expense
Statement, Tenant shall have the right to notify Landlord if it intends to
examine Landlord's books and records with respect to such Expense Statement. If
Tenant so notifies Landlord, then Tenant and its representatives shall have the
right, at Tenant's expense, during normal business hours for a period of ninety
(90) days after Tenant's notice, to examine Landlord's books and records
relating to Basic Costs for the Building for the previous Fiscal Year. Tenant
shall notify Landlord within such ninety- (90) day period if it disputes such
Expense Statement setting forth the reasons therefor (a "Notice of Dispute"). If
Tenant either (i) fails to notify Landlord of its

                                      -7-
<PAGE>

intention to examine Landlord's books and records within thirty (30) days after
delivery of an Expense Statement, or (ii) fails to give Landlord a Notice of
Dispute within the ninety- (90) day period of examination hereinabove referred
to, then Tenant shall be deemed to have accepted such Expense Statement for all
purposes hereunder. If Landlord shall have overstated Tenant's obligation for
Basic Costs for any calendar year, Landlord shall promptly refund such excess.

                (d)  If the Term ends on a date other than the last day of a
Fiscal Year, then the actual Basic Costs incurred during the Fiscal Year in
which the Expiration Date occurs (as the same may be adjusted pursuant to the
last paragraph of Section 6.02) shall be computed and an appropriate proration
shall be made so that Tenant pays that portion of its Proportionate Share of
Basic Costs Excess incurred during such Fiscal Year determined by reference to a
fraction, the numerator of which is the number of days during such Fiscal Year
that are included in the Term, and the denominator of which is the number of
days in such Fiscal Year.

        Section 6.02.  As used herein, "Basic Costs" means all expenses, costs,
        -------------
and disbursements described hereinafter (net of discounts, credits, rebates or
direct reimbursements, including, without limitation, reimbursement from tenants
or other third-parties or from any insurance company or under-writer) which
Landlord incurs in connection with the operation, repair, and maintenance of the
Building (including all facilities installed in subsequent years if such
facilities are commonly installed in similar first-class office buildings in
Washington, D.C.) computed on an accrual basis. All Basic Costs shall be
determined according to generally accepted accounting principles. Basic Costs
shall include the following:

                (a)  Wages, salaries, and fees of all personnel or entities
(exclusive of Landlord's executive personnel) engaged in the operation, repair,
maintenance, or security of the Building, including taxes, insurance, and
benefits relating thereto and on-site rental paid by the Building manager;
provided, however, that if during the Term such personnel or entities are
working on projects being periodically developed or operated by Landlord as well
as the Building, their wages, salaries, fees, and related expenses shall be
appropriately allocated among all of such projects (based on time records to be
maintained by all personnel engaged in such projects or on some other reasonable
method of allocation) and only that portion of such expenses reasonably
allocable to the Building shall be included as a "Basic Cost"

                (b)  All supplies and materials used in the operation, repair,
security, and maintenance of the Building.

                (c)  Costs of all maintenance, janitorial, security and service
agreements for the Building and the equipment therein, including, without
limitation, alarm service, water treatment services, janitorial services, window
leaning, service on electrical and mechanical components, rubbish removal,
elevator maintenance, extermination service, plumbing service, and interior and
exterior landscaping.

                (d)  Cost of all insurance relating to the Building for which
Landlord is responsible hereunder, or which Landlord considers reasonably
necessary for the operation of the Building, including, the cost of property,
casualty and liability insurance applicable to the Building and Landlord's
personal property used in connection with the maintenance, repair and operation
of the Building (not including any personal property used by Landlord in
connection

                                      -8-
<PAGE>

with its occupancy of any of the Building). If during any Fiscal Year (or
partial Fiscal Year) during the Term (including the Fiscal Year in which the
Commencement Date occurs), Landlord elects to self-insure with respect to
property insurance in accordance with Section 15.06, Basic Costs shall include
the cost which Landlord would otherwise have incurred at competitive prevailing
rates to obtain such property insurance for the Building; provided, however,
that when and if Landlord first elects to self-insure with respect to property
insurance on or after the Commencement Date, the deemed cost (determined on a
daily basis) of such self-insurance included in Basic Costs during the first
twelve (12) months next ensuing (or during such lesser period while Landlord
continues to self-insure with respect to property insurance) shall not
thereafter increase and shall at all times thereafter while Landlord elects to
self-insure with respect to property insurance be conclusively deemed to be the
cost (determined on a daily basis) of Landlord's self-insurance with respect to
property insurance for purposes of computing Basic Costs during any period under
this lease, except that in the event Landlord elects on one or more additional
times to self-insure with respect to property insurance after having had such
insurance provided by a third-party insurance company for a continuous period in
excess of five (5) years, then the maximum dollar amount of property insurance
which can be included in Basic Costs during such self-insurance period shall be
the cost of the third-Party insurance incurred by Landlord during the full
Fiscal Year immediately preceding the year in which Landlord so elected to self-
insure.

                (e)  All utility costs of common areas of the Building (that is
areas not devoted to office or retail space) including, without limitation,
costs of water, power, fuel, heating, lighting, air conditioning, and
ventilating and fees of engineers or electrical consulting firms engaged to do
work relating to such utility costs or the determination thereof, it being
understood and agreed that the electricity consumed to provide heating,
ventilating and air-conditioning to the common areas in central pumps and
facilities for providing heated and chilled to the entire Building shall be
determined by metering the electrical consumption of such central pumps and
facilities and by allocating the cost of such electricity in proportion to the
relative number of Btu's taken from (for heating) or added to (for air-
conditioning) the stream of heated and chilled water delivered to the air-
handling units serving the common areas as compared to the number of Btu's taken
from or added to (as applicable) the stream of heated and chilled water
delivered to the air-handling units serving all portions of the Building other
than the common areas, with Landlord to provide and maintain all meters
necessary to perform such allocation.

                (f)  Cost of repairs and maintenance of the Building.

                (g)  Amortization of the cost of installation of capital
improvement items (i) which are primarily to reduce operating costs for the
general benefit of the Building's tenants but not in excess of the reasonably
anticipated amount of yearly savings of operating costs resulting from such
capital improvements as determined by Landlord in good faith, (ii) which are
reasonably necessary for the continued operation of the Building as first-class
office building, or (iii) which are necessary to comply with a statute, rule,
regulation or directive promulgated by any governmental authority after the
Commencement Date, together with interest on the unamortized cost at the rate of
the Prime Rate. All such costs shall be amortized over the reasonable life of
the capital investment items, with the reasonable life and amortization schedule
being determined in accordance with generally accepted accounting principles.

                                      -9-
<PAGE>

                (h)  Landlord's reasonable direct costs for the preparation of
Expense Statements for both outside accountants and accountants employed by
Landlord.

                (i)  A management fee or allowance, whether or not actually paid
by Landlord to a contract manager of the Building during a Fiscal Year, equal to
three percent (3%) of the Rental per square foot of Rentable Area payable under
this lease multiplied by the greater of (x) 90% of the Rentable Area of the
Building, or (y) the weighted daily average number of square feet of Rentable
Area of the Building occupied by tenants (including Landlord to the extent
Landlord occupies space in the Building) during the Fiscal Year. In the event
the Building is managed by a contract manager, Basic Costs shall not include
both the fee actually paid to such contract manager and an additional three
percent (3%) of the amounts specified above. Further, in any event, there shall
be excluded from Basic Costs under Section 6.02(a) the wages, salaries and fees
(and taxes, insurance and benefits and benefits related thereto) for the time of
personnel or entities devoted to performing management services or functions.

                (j)  Legal and appraisal fees relating to the operation, repair
or maintenance of the Building, including legal fees incurred in order to reduce
Basic Costs, including without limitation the costs (including expert witness
fees) incurred by Landlord in the filing, institution and prosecution of any
application or proceeding filed or instituted by Landlord in order to reduce the
taxes included in Basic Costs.

                (k)  The reasonable maintenance and repair costs which Landlord
would have incurred (and which would otherwise be included in Basic Costs) in
the absence of manufacturers and vendors warranties.

                (l)  One sixth (1/6th) of the costs of those items or services
which benefit generally the occupants of the INTELSAT Headquarters Building
consisting of landscaping and ground maintenance costs, the costs of snow
removal, costs of periodically washing both the exterior and interior of the
INTELSAT Headquarters Building, and the cost of diesel fuel for the emergency
generator.

          If during all or part of any Fiscal Year (or partial Fiscal Year) of
the Term, Landlord shall not furnish any particular item of work or service
(which would constitute an item of Basic Costs hereunder) to 100% of the Rent-
able Area of the Building (and Landlord's total cost of supplying such items of
work or service to the Building is less than it otherwise would have been had
Landlord supplied such item to 100% of the Rentable Area of the Building),
because (i) less than all of the Building is occupied or (ii) such item of work
or service is not desired or required by any tenant, or (iii) any tenant is it
self obtaining and providing such item of work or service, then an adjustment
shall be made in computing the Basic Costs for such Fiscal Year (or partial
Fiscal Year) so that the Basic Costs shall be increased for such Fiscal Year (or
partial Fiscal Year) to the amount that would have been reasonably incurred had
Landlord provided such item of work or service to 100% of the Rentable Area of
the Building for the entire Fiscal Year (or partial Fiscal Year).

        Section 6.03.  Notwithstanding anything in Section 6.02 to the contrary,
        -------------
Basic Costs shall not include:

                                     -10-
<PAGE>

                (a)  any tenant work performed or alteration of space leased to
Tenant or other tenants or occupants of the Building, whether such work or
alteration is performed for the initial occupancy by such tenant or occupant or
thereafter or any work or service performed or alteration or improvement of
space provided to or for any tenant or occupant of the Building for which a
separate or special charge would be made to Tenant under the terms of this lease
if such work or service were performed or alteration or improvement of space
were provided by Landlord to or for Tenant, or which work, service, alteration
or improvement is of a nature that Landlord is not required to provide or
perform same to or for Tenant under the terms of this lease without imposing an
additional charge therefor as additional Rental or in addition to the Rental
otherwise payable under the terms hereof;

                (b)  costs of negotiation, preparation, amendment, extension or
enforcement of leases or which are incurred in connection with any dispute
between Landlord and any tenant or as a consequence of any violation of or
breach of a lease by any tenant;


                (c)  interest and amortization of indebtedness or any costs of
financing or refinancing, depreciation or ground rent (other than any amount
payable by Landlord for insurance or repairs or other items of Basic Costs under
any ground lease, to the extent such amounts are otherwise includable in Basic
Costs under Section 6.02 and 6.03 hereunder);

                (d)  compensation paid to officers or executives of Landlord
(other than to the extent included in the management fee referred to in Section
6.02(i));

                (e)  leasing commissions and advertising and promotional
expenses and any other costs of leasing or attempting to lease space in the
Building;

                (f)  electricity consumption other than as specifically provided
in Section 6.02(e), and Utility Costs as defined in Section 8.01(b), and any
Real Estate Taxes defined in Section 9.02 (a).

                (g)  If any partnership, joint venture, corporation or other
entity controlled by Landlord or in which Landlord owns any interest (other than
a minority interest in stock of a publicly-held corporation) (a "Landlord's
Affiliate") shall provide any materials or perform any work or provide any
services the cost of which is included in "Basic Costs" hereunder, the amount of
the charges of such Landlord's Affiliate for such materials, work or services to
be included in "Basic Costs" shall be limited to reasonable charges not in
excess of the charges for similar materials, work or services which would be
charged by an independent entity engaged in the business of providing or
performing such materials, work or services under a competitive contract
negotiated in good faith at arm's length; and the charges of such Landlord's
Affiliate included in "Basic Costs" shall further be reduced by the amounts, if
any, of the charges for the time of personnel (if any) employed or used by such
Land-lord's Affiliate in providing such services or performing such work which
is otherwise charged directly as a part of "Basic Costs" of operating,
maintaining or repairing the Building under Section 6.02(a);

                (h)  Costs of structural repairs and costs of replacement,
repair, restoration or reconstruction of the Building or any part thereof or
facilities or improvements therein

                                     -11-
<PAGE>

necessitated by damage thereto or destruction thereof caused by fire, storm,
explosion or other casualty;


                (i)  Rental paid under any lease of elevators, air-conditioning
or heating equipment or machinery, emergency generators or other equipment or
machinery normally regarded as capital items unless such equipment (A) is used
for repair work or in an emergency situation and (B) is leased for a term of
three (3) months or less (but not including any lease which provides or is
accompanied by an option of Landlord to purchase the equipment or machinery
leased);

                (j)  Charges for any inventory of consumable supplies for use in
the Building prior to the time such supplies are actually taken out of inventory
for use in the Building;

                (k)  Compensation of clerks or other personnel working in any
commercial concession or business operated by Landlord or any Landlord's
Affiliate in the Building;

                (l)  Except as otherwise provided in Article 26, any costs or
expenses of operating, maintaining or repairing any parking spaces, parking
areas or parking facilities in or about the Building or Land.

        Section 6.04.  If the number of square feet of the Rentable Area of the
        -------------
Premises changes (by reason of the exercise by Tenant of its option pursuant to
Article 33 or otherwise), then Tenant's Proportionate Share shall be adjusted
effective as of the date of any such change in accordance with Section 1.02
hereof. Any charges made pursuant to this Section 6.04 shall not alter the
computation of Basic Costs as provided in Section 6.02 of this lease. If
Tenant's Proportionate Share is adjusted, the reconciliation payments for
Tenant's Proportionate Share of Basic Costs Excess pursuant to Section 6.01(b)
for the Fiscal Year in which such change occurs shall be computed based on the
daily weighted average of Tenant's Proportionate Share during such Fiscal Year.

                                   ARTICLE 7

                SERVICES BY LANDLORD AND LANDLORD'S OBLIGATIONS

        Section 7.01.    While Tenant is occupying the Premises and is not in
        -------------
default under this lease, Landlord shall furnish the Premises with: (a)
passenger elevator service in common with other tenants for access to and from
the Premises twenty-four (24) hours per day and seven (7) days per week;
provided, however, that Landlord may reasonably limit the number of elevators to
be operated during periods of construction or for safety or maintenance
purposes; and (b) the services provided for in Section 8.02. In addition, while
Tenant is occupying the Premises and is not in default under this lease,
Landlord shall make available to Tenant for Tenant's use, freight elevator
service at the loading dock of the INTELSAT Headquarters Building during normal
business hours, and shall make such service available to Tenant after normal
business hours upon reasonable prior notice. If Tenant requires services which
are not specified herein and Landlord provides such services to Tenant, Tenant
will pay to Landlord, upon demand, as additional Rental, the actual cost
incurred by Landlord to provide such services including a reasonable allocation
of Landlord's overhead, administrative and related costs.

                                     -12-
<PAGE>

        Section 7.02.    Landlord shall operate the Building as a first-class
        -------------
District of Columbia modern office building. Landlord, at its cost and expense,
shall keep and maintain the Building, its fixtures, appurtenances, systems and
facilities, and the sidewalks, plazas and landscaped areas adjoining the
Building, in good working order, condition and repair and shall make all
repairs, structural and otherwise, interior and exterior, ordinary or
extraordinary, as and when needed in or about the Premises or the Building,
except the leasehold improvements and those repairs for which Tenant is
expressly responsible pursuant to any other provisions of this lease. Landlord
shall, at its expense, finish, decorate and maintain the elevator lobbies and
all other common areas in the Building, and the floors, ceilings and surface of
all walls adjacent thereto, in a manner and of a quality consistent with a
first-class District of Columbia modern office building.

        Section 7.03.    Landlord, at its cost and expense, shall:
        -------------

                     (i)  keep the sidewalks, plazas and landscaped areas
adjoining the Building free of accumulation of snow and ice, dirt, refuse,
rubbish and unlawful obstructions;

                     (ii) keep the lobbies, common and public areas of the
Building clean and presentable;

                     (iii)  care for and maintain the shrubbery, planting and
landscaping, if any, on the plaza or plazas adjacent to the Building or other
public areas of the Building; and

                     (iv) provide Tenant, its employees and invitees prompt
access (in a manner consistent with a first-class modern office building in the
District of Columbia) into the Building (through the lobby) and the Premises
twenty-four (24) hours each day, seven (7) days per week, subject to such
reasonable security regulations as may be imposed by Landlord from time to time.

                     (v)  Provide and maintain a building directory on the
ground floor of the Building adjacent to the entrance and elevator lobby to
provide listing for Tenant and up to thirty six (36) listings for departments
and executives or employees of Tenant, of a quality and style consistent with
building directories customarily provided in first-class office buildings in
Washington, D.C.

        Section 7.04.  Nothing contained in this Article 7 or Section 8.02 [or
        -------------
any other provision of this lease] shall preclude Landlord from including in
Basic Costs (pursuant to Sections 6.02 and 6.03) any of the costs and expenses
referred to in this Article 7 or any other provision of this lease to the extent
the same are within the definition of Basic Costs.

                                   ARTICLE 8

                                   UTILITIES

        Section 8.01.    (a) Landlord shall, at Landlord's expense, install a
        -------------
meter or meters to determine the electricity directly furnished to the Premises,
and a meter or meters to determine the electricity furnished to a separate air
cooling chiller serving only the Premises. Tenant shall pay when due the cost
for such electricity directly to the supplying utility company. Landlord

                                     -13-
<PAGE>

shall also meter, at no cost to Tenant, all electricity directly furnished to
Pods L and M of the Building, and Tenant shall not be liable or responsible for
the cost of such electricity.

                (b)  As used herein, the term "Utility Costs" means that part of
the cost of electricity used in central pumps and facilities providing heated
and chilled water for heating and air-conditioning within the entire Building
which is allocated to the Premises on a Btu basis as provided hereinafter. In
this regard, it is agreed that the electrical consumption of such central pumps
and facilities shall be metered and that a share of the cost of such electricity
shall be allocated to the Premises in proportion to the relative number of Btu's
taken from (for heating) or added to (for air-conditioning) the stream of heated
and chilled water delivered to the air-handling units serving the Premises as
compared to the number of Btu's taken from or added to (as applicable) the
stream of heated and chilled water delivered to the air-handling units serving
all portions of the Building other than the Premises, with Landlord to provide
and maintain all meters necessary to perform such allocation. In this regard, it
is further agreed that:

                     (i)  Before the beginning of each Fiscal Year during the
Term, Landlord shall furnish Tenant with Landlord's estimate of the Utility
Costs for such Fiscal Year or partial Fiscal year. By the first day of each
month during such Fiscal Year, Tenant shall pay a pro rata monthly share [one-
twelfth (1/12) in the case of an entire Fiscal Year] of the estimated Utility
Costs for such Fiscal Year or partial Fiscal Year.

                     (ii) Within sixty (60) days after the end of each Fiscal
Year during the Term (beginning with the Fiscal Year in which the Commencement
Date occurs), or as soon thereafter as reasonably practical, Landlord shall
furnish to Tenant a statement of the actual Utility Costs for such Fiscal Year
("Utility Statement"), in reasonable detail so that Tenant can determine the
manner in which Landlord calculated the Utility Costs. Each Utility Statement
shall include, but not be limited to, a statement as to the relative numbers of
Btu's taken from or added to the stream of heated and chilled water delivered to
the air-handling units serving (i) the Premises, (ii) the common areas, and
(iii) all portions of the Building other than the Premises and common areas, and
the amounts of electricity costs allocated to such three respective portions of
the Building for the Fiscal year involved.

                     (iii)  Within thirty (30) days after the delivery of the
Utility Statement, Tenant shall make a lump sum payment to Landlord equal to the
amount, if any, by which the actual Utility Costs exceeds the estimated payments
toward Utility Costs paid by Tenant for such previous Fiscal Year.

                     (iv) If the actual Utility Costs is less than the estimated
payments toward Utility Costs paid by Tenant for such previous Fiscal Year,
Landlord shall refund the excess to Tenant within thirty (30) days after the
issuance of the Utility Statement or, at Landlord's option, Landlord shall apply
such amount to the next payments of Rental due hereunder.

                     (v)  The effect of the reconciliation payment or adjustment
pursuant to (iii) and (iv) above is that Tenant shall pay during each Fiscal
Year during the Term the actual Utility Costs.

                                     -14-
<PAGE>

                (c)  If the Commencement Date occurs on a date other than the
first day of a Fiscal Year, or the Term ends on a date other than the last day
of a Fiscal Year, then the actual Utility Costs incurred during such partial
Fiscal Year in which the Commencement Date or the Expiration Date, as
applicable, occurs shall be computed and an appropriate calculation shall be
made so that Tenant pays only the Utility Costs incurred during such partial
Fiscal Year.

                (d)  Within thirty (30) days after delivery of a Utility
Statement, Tenant shall have the right to notify Landlord that it intends to
examine Landlord's books and records with respect to such Utility Statement. If
Tenant so notifies Landlord, then Tenant and its representatives shall have the
right, at Tenant's expense during normal business hours for a period of ninety
(90) days after Tenant's notice, to examine Landlord's books and records with
respect to the calculation and determination of Utility Costs for the previous
Fiscal Year. Tenant shall notify Landlord within such ninety (90) day period if
it disputes such Utility Statement, setting forth the reasons therefor (a
"Notice of Dispute"). If Tenant either (i) fails to notify Landlord of its
intention to examine Landlord's books and records within thirty (30) days after
delivery of a Utility Statement, or (ii) fails to give Landlord a Notice of
Dispute within the ninety (90) day period of examination hereinabove referred
to, then Tenant shall be deemed to have accepted such Utility Statement for all
purposes hereunder. If Landlord shall have overstated Tenant's obligation for
Utility Costs for any Fiscal Year or partial Fiscal Year, Landlord shall
promptly refund such excess with interest at the Prime Rate from the date paid
by Tenant to the date refunded by Landlord.

        Section 8.02.  Landlord shall, at Landlord's expense, install, operate
        -------------
and maintain all necessary machinery and equipment to provide heated and chilled
water adequate to provide air-conditioning and heating to the Premises twenty-
four (24) hours per day, seven (7) days per week, at such temperatures and in
such amounts as are customarily provided to tenants occupying comparable space
(and operating twenty-four (24) hours per day) in first-class office buildings
in Washington, D.C., and in compliance with the specifications of Exhibit C-1.
While Tenant is occupying the Premises and is not in default under this lease,
Landlord shall furnish Tenant with the following services: (a) potable water and
heated water at those points of supply provided for normal lavatory use by
tenants in the Building; (b) heating, ventilating, and/or air conditioning in
the common and public areas of the Building twenty-four (24) hours per day,
seven (7) days per week, at such temperatures and in such amounts as may
customarily be provided to tenants occupying comparable space in first-class
office buildings (operating twenty-four hours per day) in Washington, D.C.

        Section 8.03.    At Landlord's expense, Landlord will provide feeders
        -------------
and risers to provide electrical current to the Building and to each of the
floors of the Premises in compliance with the specifications of Exhibit C-1. Any
additional riser or risers or wiring hereafter required to meet Tenant's excess
electrical requirements will, upon Tenant's written request, be installed by
Landlord at Tenant's sole cost (if the same are necessary and will not cause
permanent damage or injury to the Building or to the Premises or cause or create
a dangerous or hazardous condition, or entail excessive or unreasonable
alterations, repairs, or expense or interfere with or disturb other tenants or
occupants).

        Section 8.04.    Failure to furnish, or any stoppage of, the services
        -------------
provided for in Article 7 above and this Article 8 resulting from any cause will
not make Landlord liable in any

                                     -15-
<PAGE>

respect for damages to either person, property, or business, nor construed as an
eviction of Tenant, nor entitle Tenant to any abatement of rent, nor relieve
Tenant from its obligations under this lease. Should any malfunction of the
Building improvements or facilities occur, Landlord will repair such malfunction
promptly with reasonable diligence, but Tenant will have no claim for rebate,
abatement of rent or damages because of malfunctions or any interruptions in
service. Notwithstanding the foregoing, in the event of any such malfunction or
interruption in service which (i) is within Landlord's reasonable control to
remedy, (ii) renders the Premises untenantable to such extent that Tenant cannot
reasonably conduct its normal business operations in all or substantially all of
the Premises, and (iii) is continuous for ten (10) consecutive days, Rental
shall be abated for the period of time such malfunction or interruption in
service continues beyond such ten- (10) day period; and in addition, if any such
malfunction or interruption in service which (i) is within Landlord's reasonable
control to remedy, (ii) renders the Premises untenantable to such extent that
Tenant cannot reasonably conduct its normal business operations in all or
substantially all of the Premises, and (iii) is continuous for ninety (90)
consecutive days (which ninety- (90) day period shall be extended by force
majeure circumstances), the Tenant may, at its election, terminate this lease by
giving Landlord written notice of such election at any time thereafter prior to
the restoration of such services, in which event this lease shall terminate as
of the date of such notice, and except for those matters which specifically
survive termination hereof, the parties shall be relieved of all further
obligations and responsibilities under this lease.

                                   ARTICLE 9

                               REAL ESTATE TAXES

        Section 9.01.    Landlord believes that the Land and the INTELSAT
        -------------
Headquarters Building are not subject to the imposition of real estate taxes but
Landlord desires to provide for the payment by Tenant of its share of real
estate taxes in the event that by reason of a change in ownership of Landlord's
interest or otherwise any real estate taxes are imposed with respect to the Land
and/or the INTELSAT Headquarters Building.

        Section 9.02.    For purposes of this Article 9, the following terms
        -------------
shall have the following meanings:

                (a)  "Real Estate Taxes" shall mean all taxes, assessments, and
other governmental charges (including vault rentals, if any,) applicable to the
Land, the INTELSAT Headquarters Building, or any portion thereof, or to
Landlord's personal property used in connection with the maintenance and
operation thereof (not including any personal property used in connection with
Landlord's occupancy of any part of the INTELSAT Headquarters Building). In
addition, if at any time during the Term there shall be levied, assessed, or
imposed on Landlord or the Land and/or the INTELSAT Headquarters Building by any
governmental authority, any general or special ad valorem or other charge or tax
directly upon rentals received under leases covering space in the INTELSAT
Headquarters Building, or if any fee, tax, assessment or other charge is imposed
which is measured by or based, in whole or in part, upon such rents, or if any
charge or tax is made based directly or indirectly upon the transactions
represented by leases covering space in the INTELSAT Headquarters Building, or
the occupancy or use thereof, such taxes, fees, assessments, or other charges
shall be included as "Real Estate

                                     -16-
<PAGE>

Taxes;" provided, however, that any inheritance, estate, gift, franchise,
corporation, income, excess profit, transfer, net profits tax, sales tax or
excise tax (other than those specified in Section 9.03, which shall not be
included in the term Real Estate Taxes, but which Tenant shall pay directly to
the extent provided in Section 9.03), or special assessments for public
improvements, which may be assessed against Landlord shall be excluded from
"Real Estate Taxes;" and provided, further, that any amount of any tax which is
borne by any other tenant or is reimbursed to Landlord by any other tenant other
than under a rental adjustment provision of such tenant's lease corresponding
generally to this Article 9 shall be excluded from "Real Estate Taxes" (as, for
example and not by way of limitation, taxes assessed against particular
leasehold improvements or other facilities, alterations constructed or installed
by a tenant and which such tenant is required to bear and pay or for which such
tenant is required to pay specific reimbursement to Landlord).

                (b)  "Tax-Qualified Area" shall mean all rentable space in the
INTELSAT Headquarters Building which, for the tax year in question, is exempt
from Real Estate Taxes.

                (c) "Non-Tax-Qualified Area" shall mean all rentable space in
the INTELSAT Headquarters Building other than space which is Tax-Qualified Area.

                (d)  "Per Square Foot Amount of Base Real Estate Taxes" shall
mean the sum of (i) Two Dollars and fifty cents ($2.50) and (ii) sixty percent
(60%) of the amount by which (A) the annualized Per Square Foot Amount of Real
Estate Taxes for the first tax year during which Real Estate Taxes are assessed
upon any Non-Tax-Qualified Area exceeds (B) Two Dollars and fifty cents ($2.50).

                (e)  "Per Square Foot Amount of Real Estate Taxes" for any tax
year shall mean the quotient derived by dividing (i) the Real Estate Taxes for
such tax year, by (ii) the number of square feet of Rentable Area of the
INTELSAT Headquarters Building that is Non-Tax-Qualified Area for such tax year;
provided, however, that, if the Real Estate Taxes which are imposed upon or
assessed against or with respect to or based on the value of the Land (as
distinguished from the Non-Tax-Qualified Area of the INTELSAT Headquarters
Building) reflect an amount that would be payable if there were no tax-exempt
organizations or other entities occupying space in the INTELSAT Headquarters
Building, then the "Per Square Foot Amount of Real Estate Taxes" for such tax
year shall mean the sum of (i) the quotient derived by dividing (A) the Real
Estate Taxes for such tax year, less all amounts, if any, of such Real Estate
Taxes which are imposed upon or assessed against or with respect to or based on
the value of the Land (as distinguished from the Non-Tax-Qualified Area of the
INTELSAT Headquarters Building), by (B) the number of square feet of Rentable
Area of the INTELSAT Headquarters Building that is Non-Tax-Qualified Area for
such tax year, plus (ii) the quotient derived by dividing (A) the amount, if
any, of the Real Estate Taxes for such tax year which are imposed upon or
assessed against or with respect to or based on the value of the Land (as
distinguished from the Non-Tax-Qualified Area of the INTELSAT Headquarters
Building), by (B) the number of square feet of Rentable Area of the entire
INTELSAT Headquarters Building.

                (f)  "Tenant's Proportionate Tax Share" for any tax year shall
mean the product of (i) the number of square feet of Rentable Area of the
Premises that is Non-Tax-

                                     -17-
<PAGE>

Qualified Area for such tax year, times (ii) the excess, if any, of the Per
Square Foot Amount of Real Estate Taxes for such tax year over the Per Square
Foot Amount of Base Real Estate Taxes.

        Section 9.03.  During the Term Tenant shall pay to Landlord, as
        -------------
additional rent, Tenant's Proportionate Tax Share. In the event that sales tax
or excise tax is imposed by any governmental authority on the rent payable by
Tenant hereunder, such sales tax or excise tax shall be paid by Tenant. Landlord
shall submit to Tenant a copy of the bill for Real Estate Taxes and a statement
of Tenant's Proportionate Tax Share. Tenant shall pay Tenant's Proportionate Tax
Share for the tax year to which such amount applies, in the same number of
installments as the Real Estate Taxes are payable to the taxing authority
payable in said year, at least thirty (30) days prior to the due date for each
such installment.

        Section 9.04.    If the Commencement Date or the Expiration Date does
        -------------
not coincide with the first or last day of a tax year, respectively, then, with
respect to the tax year in which such Commencement Date or Expiration Date
occurs, Tenant's Proportionate Tax Share shall be prorated based upon the number
of days in such tax year during which this lease is in effect. If Landlord
receives any refunds of Real Estate Taxes for a tax year falling wholly or
partly within the Term, Landlord shall promptly recompute Tenant's Proportionate
Tax Share and deliver to Tenant a statement showing such recomputation together
with interest, if any, received by Landlord from the taxing authorities on the
amount of such overpayment. Within ten (10) days after the later of (i) the date
on which Landlord's right to such refund becomes final or (ii) the date on which
Landlord receives such refund, Landlord shall refund to Tenant any overpayment
of Tenant's Proportionate Tax Share for the tax year in question, together with
interest, if any, received by Landlord from the taxing authorities on the amount
of such overpayment, together with interest on such overpayment at the Prime
Rate per annum for any period after Landlord received such tax refund to the
date when Landlord remits such overpayment to Tenant. The fact that Landlord
might become obligated to make a refund to Tenant at some future time shall not
cure any default by Tenant in failing to make timely payments of its liability
for Tenant's Proportionate Tax Share.

        Section 9.05.    For Purposes hereof, the Rentable Area of the INTELSAT
        -------------
Headquarters Building shall be determined in accordance with Exhibit E.

                                  ARTICLE 10

                          USE AND LEGAL REQUIREMENTS

     The Premises shall be used only for the operation of a television broadcast
station and related studio and office space and for no other purpose.  If at any
time Tenant shall be prohibited by "Legal Requirements", or by virtue of any
provision of the Ground Lease from (i) using the Premises for the operation of a
television broadcast station and related studio and office space (which
prohibition cannot be remedied by a commercially feasible change in Tenant's
method of operation), or (ii) installing, operating or maintaining the
Communication Systems and there are no commercially feasible alternative systems
performing comparable functions that can be installed by Tenant, Tenant shall
have the right, at is election, by giving written notice of termination to
Landlord, to terminate this lease, in which event the Term of this lease will
end on the date of giving of such notice to Landlord with the same effect as if
such date were the

                                     -18-
<PAGE>

Expiration Date elsewhere herein defined. Tenant agrees to use and maintain the
Premises in a clean, careful, safe, lawful, and proper manner. Tenant shall, at
its sole expense (i) comply with all valid laws, orders, ordinances, regulations
applicable to the Premises of Federal, state, county, municipal and other
authorities ("Legal Requirements"), (ii) comply with any direction made pursuant
to law by any public officers requiring abatement of any nuisance, or which
imposes upon Landlord or Tenant any duty or obligation arising from tenant's
occupancy or use of the premises from conditions which have been created by or
at the insistence of Tenant, and (iii) indemnify Landlord and hold Landlord
harmless from any loss, cost, which Landlord may incur or suffer by claim, or
expense reason of Tenant's failure to comply with its obligations under clauses
(i) or (ii) above. If Tenant receives notice of any such direction or of
violation of any such law, order, ordinance, or regulation, it shall promptly
notify Landlord thereof.

                                  ARTICLE 11

                      OBSERVANCE OF RULES AND REGULATIONS

     Tenant and its servants, employees, agents, visitors, and licensees shall
observe faithfully and comply with the Rules and Regulations (herein so called)
attached to this lease as Exhibit F.  Landlord shall at all times have the right
to make reasonable changes in and additions to such Rules and Regulations,
provided such changes in existing or new Rules and Regulations do not materially
interfere with the lawful conduct of Tenant's business in the Premises.  Any
failure by Landlord to enforce any of the Rules and Regulations now or hereafter
in effect, either against Tenant or any other tenant in the Building, shall not
constitute a waiver of any such Rules and Regulations.  Landlord shall not be
liable to Tenant for the failure or refusal by any other tenant, guest, invitee,
visitor, or occupant of the Building to comply with any of the Rules and
Regulations.  Anything herein contained to the contrary notwithstanding, in the
event any Rule or Regulation is not enforced in a uniform and non-discriminatory
manner, such Rule or Regulation shall not be enforceable against Tenant.

                                  ARTICLE 12

                                  ALTERATIONS

        Section 12.01.      Tenant may not, at any time during the Term, without
        --------------
Landlord's prior written consent, make any alterations to the Premises which (i)
in Landlord's judgment affect the structure or the safety of the Building, (ii)
in Landlord's judgment affect the Building electrical, HVAC, plumbing or
mechanical systems or the functioning thereto outside the Premises, (iii) in
Landlord's judgment fail to comply with applicable Legal Requirements or (iv)
front upon or are located Within twelve (12) inches from any window (other than
any walls which join any window or exterior wall). If Tenant desires to make any
alterations in or to the Premises, Tenant shall, prior to beginning any such
work, deliver to Landlord all plans or drawings and specifications therefor,
whether or not Landlord's approval is recurred for such alterations. If
Landlord's approval is required pursuant to the first sentence of this Section
12.01, Tenant shall nay to Landlord reasonable costs incurred by Landlord for
third-party consultants to review such plans and specifications. Tenant may
proceed to the construction of the alterations provided that (i) Tenant has
received Landlord's approval thereof, if required pursuant to the first sentence
of this Section 12.01, (ii) the alterations are in strict compliance with the
plans and

                                     -19-
<PAGE>

specifications submitted to Landlord and with the provisions of this Article 12;
(iii) Tenant Shall indemnify and hold Landlord harmless against and from any and
all claims, damages, costs and finest arising out of or connected with such
alterations, and (iv) Tenant shall procure at its own expense such governmental
approvals and permits as may be required for such alterations. Landlord shall
exercise reasonable good faith judgment in determining whether to approve the
plans and specifications, it being understood and agreed that if a dispute
should arise as to whether Landlord's disapproval of any plans and
specifications was exercised in Landlord's reasonable good faith judgment,
Landlord shall have no liability because of such disapproval until such time as
(i) a court of competent jurisdiction enters a final judgment not subject to
further appeal that Landlord did not exercise reasonable good faith judgment in
withholding its approval and (ii) after such final determination Landlord
continues to refuse to consent to the applicable plans and specifications. Where
Landlord's approval is required pursuant to the first sentence of this Section
12.01, such approval shall be conclusively deemed to have been granted unless
Landlord gives Tenant written notice specifying in particular its objections to
such plans and specifications within fifteen (15) days after Landlord has
received Tenant's plans or drawings and specifications for any alterations, but
only if at the time Tenant delivers the plans or drawings and specifications to
Landlord, Tenant notifies Landlord in writing that if Landlord fails to respond
within fifteen (15) days, such silence shall be deemed an approval. At Tenant's
expense, Landlord shall join in submitting Tenant's plans for any necessary
governmental approval, if required by applicable law. All alterations shall be
made at Tenant's expense by contractors which have been approved by Landlord
(which approval shall not be unreasonably delayed or withheld). All such
construction, alterations, and maintenance work done by, or for, Tenant shall
(A) be performed in a such manner as to maintain harmonious labor relations, (B)
not alter the exterior appearance of the Building or the common and public areas
thereof, (C) not affect the structure or the safety of the Building, (D) comply
with all building, safety, fire, plumbing, electrical, and other codes and
governmental and insurance requirements, (E) be completed promptly and in a good
and workmanlike manner, and (F) be performed in compliance with Article 13
hereof.

        Section 12.02.   After the completion of any alterations to the
        --------------
Premises, Tenant shall deliver to Landlord either (i) a certificate signed by
Tenant stating that such alterations have been completed in accordance with the
plans and specifications previously delivered to Landlord or (ii) a copy of "as-
built" plans and specifications with respect to such alterations.

        Section 12.03.   No alterations, leasehold improvements, and other
        --------------
physical additions made or installed by or for Tenant in or to the Premises
shall be removed during the Term except, in accordance with Section 20.02.

                                  ARTICLE 13

                                     LIENS

     Tenant shall keep the Premises and the Building free from any liens arising
from any work performed, materials furnished, or obligations incurred by or at
the request of Tenant.  All persons either contracting with Tenant's, furnishing
or rendering labor and materials to Tenant shall be notified in writing by
Tenant that they must look only to go thing contained in this lease shall be
construed as Landlord's consent to any contractor, subcontractor, laborer, or

                                     -20-
<PAGE>

materialman" or the performance of any labor or the furnishing of any materials
for any specific improvement, alteration, or repair of, or to, the Premises or
the Building, nor as giving Tenant any right to contract for, or permit the
performance of, any services or the furnishing of any materials that would
result in any liens against the Premises or the Building.  If any lien is filed
against the Premises or Tenant's leasehold interest therein, or if any lien is
filed against the Building which arises out of any purported act or agreement of
Tenant, Tenant shall discharge the same within ten (10) days after its filing by
payment, filing of the bond required by law; or otherwise.  If Tenant fails t o
discharge such lien within such period, then, in addition to any other right or
remedy of Landlord, Landlord may, at its election, discharge the lien by paying
the amount claimed to be due, by obtaining the discharge by deposit with a court
or a title company, or by bonding.  Tenant shall pay on demand any amount paid
by Landlord for the discharge or satisfaction of any such lien, and all
reasonable attorneys' fees and other costs and expenses of Landlord incurred in
defending any such action or in obtaining the discharge of such lien, together
with all necessary disbursements in connection therewith.

                                  ARTICLE 14

                                    REPAIRS

        Section 14.01.   Tenant shall keep the Premises and every part thereof
        --------------
in good condition and repair at all times during the Term and at Tenant's sole
cost and expense. If Tenant fails to make such repairs promptly, Landlord, at
its option, may make such repairs, and Tenant shall pay Landlord on demand
Landlord's actual costs in making such repairs. Notwithstanding the foregoing,
Tenant shall have no obligation to maintain or repair any portion of the
Building which is not part of the Premises; provided, however, that Tenant shall
reimburse Landlord for any actual costs incurred for maintenance or repair of
any such portion of the Building if such maintenance or repair is necessitated
by the negligent acts or omissions of Tenant. At the end of the Term, Tenant
shall surrender to Landlord the Premises and all alterations, additions and
improvements thereto subject to the provisions of Article 20 hereof. Landlord
has no obligation and has made no promise to alter, remodel, improve, repair,
redecorate, or paint the Premises or any part thereof, except as specifically
set forth in this lease. No representations respecting the condition of the
Premises or the Building have been made by Landlord to Tenant except as
specifically set forth in this lease.

        Section 14.02.
        --------------

                (a)  Subject to the other provisions of this lease imposing
obligations in this respect upon Tenant, and subject to the provisions of
Articles 16 and 17 hereof, Landlord shall repair, replace, and maintain (i) the
external and structural parts of the Building, (ii) all common and public areas
of the Building (including the parking garage), and (iii) the HVAC, mechanical,
electrical and plumbing systems of the Building exclusive of systems, if any,
specially installed by or on behalf of any tenant; provided that, the HVAC,
mechanical, electrical and plumbing systems of the Building to be installed by
Landlord under the terms of this lease or under the terms of Exhibit C hereto
shall not be deemed to have been "specially installed by or on behalf of any
tenant" for purposes of this Section 14.02 (other than the supplemental air-
conditioning chiller which Landlord shall initially install for Tenant at
Landlord's cost and expense, which chiller Tenant shall maintain and repair
during the Term but need not replace).

                                     -21-
<PAGE>

                (b)  Nothing contained in this Section 14.02 shall preclude
Landlord from including in Basic Costs (pursuant to Sections 6.02 and 6.03) any
of the costs and expenses referred to herein to the extent the same are within
the definition of Basic Costs.

                                  ARTICLE 15

                                   INSURANCE

        Section 15.01.    During the Term, Tenant, at its sole expense, shall
        --------------
obtain and keep in force the following insurance:

                (a)  All Risk insurance upon property of every description and
kind owned by Tenant and located in the Building owned by Tenant and located in
the Building or for which Tenant is legally liable or installed by or on behalf
of Tenant, including without limitation, furniture, fittings, installations,
furnishings, movable trade fixtures and personal property, and alterations, in
an amount not less than ninety percent, (90%) of the full replacement cost
thereof. All such insurance policies shall contain a waiver of subrogation in
favor of Landlord. Landlord will not be required to carry insurance of any kind
on any of Tenant's fixtures, equipment or improvements under this lease, and
Landlord shall not be obligated to repair any damage thereto or replace the
same. Tenant shall also maintain All Risk insurance covering all Non-Building
Standard Lease hold Improvements in an amount equal to not less than ninety
percent (90%) of the replacement cost thereof in excess of the replacement cost
of corresponding Building Standard Leasehold Improvement containing a waiver of
subrogation in favor of Landlord. As such term is used herein, "Building
Standard Leasehold Improvements" shall refer to leasehold improvements of the
nature and quality of the leasehold improvements heretofore installed by
Landlord in the portions of the Phase I buildings on the Land.

                (b)  Comprehensive general liability insurance coverage,
including personal injury, bodily injury, broad form property damage, operations
hazard, owner's protective coverage, contractual liability, and products and
completed operations liability, in limits not less than $5,000,000 inclusive
provided that such $5,000,000 limits may be reduced to the extent that insurance
coverage in such amount becomes unobtainable at commercially reasonable rates or
to the extent that lesser limits are, in the future, customarily maintained by
parties similarly situated and comparable to Tenant engaged in business in
Washington, D.C. All such insurance policies shall name Tenant as named insured
thereunder and shall name Landlord and Landlord's mortgagees (and, if requested
by Landlord, ground or primary lessors) as additional insureds thereunder, all
as their respective interests may appear. Such insurance may be placed as part
of any blanket policy carried by Tenant and/or carried under primary and excess
coverage policies.

                (c)  Worker's Compensation and Employer's Liability insurance as
required by law.

                (d)  Any other form or forms of insurance as Tenant, Landlord or
Landlord's mortgagee may reasonably from time to time in form, in amounts and
for insurance risks against which a prudent tenant of comparable size and in
comparable business would protect itself.

                                     -22-
<PAGE>

     All policies shall be issued by insurers of recognized responsibility.
Tenant will deliver certificates of insurance (substantially in the form of
Exhibit E hereto) to Landlord as soon as practicable after the placing of the
required insurance, but not later than ten (10) days prior to the date Tenant
takes possession of all or any part of the Premises.  All policies shall contain
an undertaking by the insurers to notify Landlord and Landlord's mortgagees
(and, if applicable, ground lessors) in writing, by certified or registered
United States mail, return receipt requested, not less than fifteen (15) days
before any material adverse change, reduction in coverage, cancellation, or
other termination thereof.

        Section 15.02.  During the Term, Landlord shall insure the Building
        --------------
Standard Leasehold Improvements (excluding any property Tenant is obligated to,
insure under Section 15.01 hereof) with a reputable insurance company against
damage with All Risk insurance in an amount not less than 90% of the then
replacement cost and Landlord shall also insure the Non-Building Standard
Leasehold Improvements that are of a similar, type, character and nature as
Building Standard Leasehold Improvements with a reputable insurance company with
All Risk Insurance in an amount not less than 90% of the full replacement cost
of those Building Standard Leasehold Improvements of a similar type, character
and nature. (All such insurance policies shall contain waive of subrogation in
favor of Tenant. Landlord shall also maintain comprehensive general liability
insurance in limits not less than the liability insurance limits required to be
maintained by Tenant pursuant to Section 15.01(b) from time to time, which
insurance policies shall waive any right of the insurer to invoke any privilege
or immunity (as an International Organization or sovereign government) of
Landlord, and shall name Tenant as an additional insured thereunder. Landlord
may, but shall not be obligated to, obtain and carry any other form or forms of
insurance as it or Landlord's mortgagees may reasonably determine advisable.
Notwithstanding any contribution by Tenant to the cost of insurance premiums, as
provided herein, Tenant acknowledges that it has no right to receive any
proceeds from any property insurance policies carried by Landlord.

        Section 15.03.   Tenant will not keep or use in or upon the Premises any
        --------------
article which may be prohibited by any insurance policy in force covering the
Building and the leasehold improvements in the Building. If Tenant's occupancy
or business in or on the Premises, whether or not Landlord has consented to the
same, results in any increase in premiums for the insurance carried by Landlord
with respect to the Building, Tenant shall pay any such increase in premiums as
additional Rental within ten (10) days after being billed therefor by Landlord.
In determining whether increased premiums are a result of Tenant's use of the
Premises, a schedule issued by the organization computing the insurance rate on
the Building or the leasehold improvements showing the various components of
such rate shall be conclusive evidence of the several items and charges which
make up such rate. Tenant shall promptly comply with all reasonable requirements
of the insurance authority or any present or future insurer relating to the
Premises. Nothing herein shall, however, be construed to prohibit Tenant from
keeping and using in the Premises any equipment or property reasonably and
customarily used for the operation of a television broadcast station and related
studio and office.

        Section 15.04.   If any of Landlord's insurance policies shall be
        --------------
cancelled or cancellation shall be threatened or the coverage thereunder reduced
or threatened to be reduced in any way because of the use of the Premises or any
part thereof by Tenant or any assignee or subtenant of Tenant or by anyone
Tenant permits on the Premises and if Tenant fails to remedy

                                     -23-
<PAGE>

the condition giving rise to such cancellation, threatened cancellation,
reduction of coverage, or threatened reduction of coverage within a reasonable
period of time after notice not to exceed ten (10) days (or such longer period
of time as is required to remedy such condition provided Tenant commences to
correct such condition within such ten- (10) day period and continues diligently
to remedy such condition to completion), Landlord may, at its option, enter upon
the Premises and attempt to remedy such condition, and Tenant shall promptly pay
the cost thereof to Landlord as additional Rental. Landlord shall not be liable
for any damage or injury caused to any property of Tenant or of others located
on the Premises resulting from such entry. If Landlord is unable, or elects not,
to remedy such condition, then Landlord shall have all of the remedies provided
for in this lease in the event of a default by Tenant. Notwithstanding the
foregoing (but subject to Section 15.03), Landlord shall be responsible for
maintaining insurance, if available, which permits Tenant to make reasonable use
of the Premises for the normal operation of a television broadcast station and
related studio and office space without regard to the foregoing provisions of
this Section 15.04, provided, however, that if Landlord is unable to obtain such
insurance and if Landlord elects not to self-insure in accordance with Section
15.06, Landlord shall have the right to terminate this lease by notifying Tenant
of such election in writing in which event, this lease shall be terminated as of
the date specified in such notice, and except for provisions hereof which
expressly survive termination, the parties shall have no further liabilities or
responsibilities under this lease.

        Section 15.05.      All policies covering real or personal property
        --------------
which either party obtains affecting the Premises or the Building shall include
a clause or endorsement denying the insurer any rights of subrogation against
the other party to the extent rights have been waived in writing by the insured
before occurrence of injury or loss. Landlord and Tenant shall not be liable or
responsible for, and each hereby releases the other, the partners, employees,
officers, directors and agents of the other from any and all liability and
responsibility to the other, or any and each hereby releases the other, the
partners, employees, officers, directors and agents of the other from any and
all liability and responsibility to the other, or any person claiming by,
through or under the Landlord or Tenant, by way of subrogation or otherwise for
any damage or loss to their respective property due to hazards covered or which
should be covered by policies of insurance obtained or which should be or have
been obtained pursuant to this lease, to the extent of the injury or loss
covered or which should have been covered thereby, assuming that any deductible
shall be deemed to be insurance coverage.

        Section 15.06.   So long as (i) International Tele-communications
        --------------
Satellite Organization is the Landlord hereunder (and has not suffered a
material and adverse change in its financial condition or strength), or (ii) if
the Landlord hereunder is not International Telecommunications Satellite
Organization but demonstrates to Tenant's reasonable satisfaction that Landlord
has sufficient financial strength to absorb such risk, and with Tenant's prior
consent in writing (such consent not to be unreasonably withheld), then Landlord
may elect to self-insure (and not obtain from an insurance company) all or part
of the property insurance required to be maintained by Landlord under the
provisions of the first, sentence of Section 15.02; provided that, to the extent
that Landlord does self-insure against any risk or hazard, Landlord hereby
releases Tenant and the partners, employees, officers, directors and agents of
Tenant, and agrees to indemnify and save and hold Tenant and its partners,
employees, officers, directors and agents harmless from any loss, cost, expense,
claim or liability whatsoever in connection with any damage or loss to any
property of Landlord due to hazards or risks which would have been covered by
policies of

                                     -24-
<PAGE>

insurance which would have been required to be maintained by Landlord under the
provisions of Section 15.02 had it not elected to self-insure against such risk
or hazard.

                                  ARTICLE 16

                       DAMACE BY FIRE OR OTIHER CASUALTY

        Section 16.01.   If the Building or the Premises shall be damaged by any
        --------------
casualty, Tenant shall immediately notify Landlord of the same and if this lease
shall not have been terminated pursuant to this Article 16, Landlord shall
repair said damage and restore and rebuild the Building and/or the Premises
(including leasehold improvements in the Premises, but excluding the property of
Tenant, and limited to the cost of repairing, restoring or rebuilding Building
Standard Leasehold Improvements in the case of Non-Building Standard Leasehold
Improvements) as soon as reasonably practicable after said damage occurs, and
the Rental payable hereunder shall be reduced or abated in proportion to the
extent that the Premises are rendered unusable for the normal conduct of the
business then conducted on the Premises until such Premises are rendered usable
for the normal conduct of such business.

        Section 16.02.   If the Premises shall be damaged or destroyed by any
        --------------
casualty such that Landlord reasonably estimates that the repair and restoration
of the Premises would require an expenditure of more than twenty-five percent
(25%) of the replacement cost of the Premises immediately prior to such
casualty, and if (i) less than three (3) years remain of the unexpired term of
this lease (as theretofore extended, if applicable) or (ii) Landlord elects to
demolish the Building (or the two (2) Pods of the Building containing the
Premises), then Landlord shall have the right to terminate this lease by written
notice to Tenant given within sixty (60) days after the date of such damage and
upon such notice this lease shall terminate; provided, however, that the
provisions of this lease which are designated to cover matters of termination
and the period thereafter shall survive the termination of this lease.

        Section 16.03.   If the Building and/or the Premises shall be so damaged
        --------------
by casualty to such extent that the premises are rendered unusable for the
normal conduct of Tenant's business then conducted on the Premises, Landlord
shall, as promptly as practicable following such casualty, obtain and deliver to
Tenant a certificate by an independent, qualified engineer or contractor setting
forth the good faith reasonable estimate of such engineer or contractor as to
the period of time required to substantially repair and restore the Building
and/or Premises so as to permit Tenant to resume the normal conduct of its said
business in the Premises. In such event:

                (a)  If such certificate reflects that such repair and
restoration cannot reasonably he completed within one hundred eighty (180) days
after the occurrence of such casualty, and if at least two (2) years remain of
the Term of this lease (including any extension of such Term as to which Tenant
has theretofore exercised an option so to extend the Term), Tenant may terminate
this lease by giving written notice of termination to Landlord within thirty
(30) days after receipt of such certificate.

                (b)  If such certificate reflects that such repair and
restoration cannot reasonably be completed within ninety (90) days after
occurrence of such casualty, and if less than two (2) years remain of the Term,
of this lease (including any extension of such Term as to

                                     -25-
<PAGE>

which Tenant has theretofore exercised an option so to extend the Term), Tenant
may terminate this lease by giving written notice of termination to Landlord
within thirty (30) days after receipt of such certificate.

                (c)  If such certificate reflects that such repair and
restoration cannot reasonably be completed within one hundred eighty (180) days
after the occurrence of such casualty, and if at least two (2) years remain of
the Term of this lease (including any extension of such Term as to which Tenant
has theretofore exercised an option so to extend the Term), and if Landlord
elects to demolish the Building (or the two Pods of the Building containing the
Premises), Landlord may terminate this lease by giving written notice of
termination to Tenant within forty-five (45) days after the occurrence of such
casualty.

                (d)  If such certificate reflects that such repair and
restoration cannot reasonably he completed within ninety (90) days after the
occurrence of such casualty, and if less than two (2) years remain of the Term
of this lease (including any extension of such Term as to which Tenant has
theretofore exercised an option so to extend the Term), Landlord may terminate
this lease by giving written notice of termination to Tenant within forty-five
(45) days after occurrence of such casualty.

     If this lease is terminated pursuant to any of the foregoing provisions of
this Section 16.03, the provisions of this lease which are designated to cover
matters of termination and the period thereafter shall survive the termination
of this lease.

        Section 16.04.  If Landlord is obligated to repair the Premises or
        --------------
Building after any casualty pursuant to this Article 16, Landlord shall
diligently commence and continuously prosecute such repair to completion.

        Section 16.05.   If the Premises, or any substantial portion thereof, is
        --------------
substantially destroyed by fire or other cause at any time during the last
twelve (12) months of the Term (as the same may have been extended), either
Landlord or Tenant may terminate this lease upon written notice to the other
given within sixty (60) days after the date of such destruction, provided,
however, that those provisions of this lease which are designated to cover
matters of termination and the period thereafter shall survive the termination
hereof. For purposes of this Section 16.05, the Premises shall be deemed
"substantially destroyed" if at least twenty-five percent (25%) of the Rentable
Area of the Premises is rendered unusable by such fire or other cause.

        Section 16.06.   No damages, compensation, or claim shall be payable by
        --------------
Landlord for inconvenience, loss of business, or annoyance arising from any
repair or restoration of any portion of the Premises, the Leasehold
Improvements, or the Building. Landlord shall use its best efforts to have such
repairs made promptly so as not to unnecessarily interfere with Tenant's
occupancy.

        Section 16.07.   The provisions of this Article shall be considered an
        --------------
express agreement governing any case of damage or destruction of the Building,
the Leasehold Improvements, or the Premises by fire or other casualty.

                                     -26-
<PAGE>

        Section 16.08.   In the event of the termination of this lease pursuant
        --------------
to the provisions of Sections 16.02, 16.03 or 16.05, this lease, the Term and
the estate hereby granted shall expire as . of the date of such termination in
the same manner and with the same effect as if it were the date set for the
normal expiration of the Term, and Rental shall be apportioned as of the date of
termination.

                                  ARTICLE 17

                                 CONDEMNATION

        Section 17.01.   In the event the whole or substantially the whole of
        --------------
the Building and/or the Premises are taken or condemned for any public purpose,
this lease shall terminate as of the date of such taking; provided, however,
that those provisions of this lease which are designated to cover matters of
termination and the period thereafter shall survive the termination hereof.

        Section 17.02.   In the event that more than fifteen percent (15%) of
        --------------
the Rentable Area of the Premises shall be taken or condemned for any public or
quasi-public purpose, which taking, in Tenant's reasonable judgment, will
interfere materially with Tenant's normal conduct of Tenant's business in the
Premises, then Tenant shall have the option to terminate this lease, effective
as of the date specified by Tenant in its notice of termination; provided,
however, that those provisions of this lease which are designated to cover
matters of termination and the period thereafter shall survive the termination
hereof.

        Section 17.03.   In the event that a portion, but less than
        --------------
substantially the whole, of the Premises should be taken or condemned for any
public purpose, then this lease shall terminate as of the date of such taking as
to the portion of the Premises so taken, and, unless Tenant exercises its option
to terminate this lease pursuant to Section 17.02, this lease shall remain in
full force and effect as to the remainder of the Premises and Landlord shall
with due diligence restore the remainder of the Premises to an architectural
unit as nearly like its condition as it existed prior to such taking as is
reasonably and practicably feasible. In such event, the Annual Rental, Tenant's
Proportionate Share of Basic Costs Excess and Tenant's Proportionate Tax Share
of Real Estate Taxes attributable to the Premises will be diminished by an
amount representing the part of such amounts properly applicable to the portion
of the Premises so taken. Further, in such event, Tenant's Proportionate Share
shall be recomputed based upon the remaining Rentable Area in the Premises and
in the Building, but the area in the Building thus taken shall continue to be
considered as Rentable Area of the Building.

        Section 17.04.   In the event of the termination of this lease pursuant,
        --------------
to the provisions of Sections 17.01, 17.02 or 17.03, this lease and the Term and
the estate hereby granted shall expire as of the date of such termination in the
same manner and with the same effect as if that were the date set for the normal
expiration of the Term, and Rental shall be apportioned as of the date of
termination. The pro-visions of this Section 17.04 shall apply in the same
manner to any partial termination this lease pursuant to the provisions of this
Article 17.

        Section 17.05.   If Landlord is obligated to repair or restore the
        --------------
Premises or the Building after any taking or condemnation pursuant to this
Article 17, Landlord shall diligently and continuously prosecute such repair or
restoration to completion.

                                     -27-
<PAGE>

        Section 17.06.   Except as otherwise provided in Section 17.07 below,
        --------------
Landlord shall be entitled to receive the entire award in any condemnation
proceeding or action for taking of the Building, Land or Premises; provided that
Tenant shall be entitled to seek and recover and retain out of the award in any
such proceeding or action damages and compensation (i) for the value of any
leasehold improvements, additions or alterations installed or constructed in the
Premises or on the Building or Land by Tenant (less the portion, if any, thereof
for which Tenant was reimbursed by Landlord pursuant to this lease) and taken in
such proceeding or action, and (ii) for the value of any property of Tenant
other than the leasehold interest of Tenant taken in such proceeding or action.

        Section 17.07.   If the temporary use or occupancy of all or any part of
        --------------
the Premises shall be condemned or taken for any public or quasi-public use
during the Term, and if more than fifteen percent (15%) of the Rentable Area of
the Premises shall be so taken, which taking, in Tenant's reasonably judgment,
will interfere materially with Tenant's normal conduct of Tenant's business in
the Premises and such temporary taking shall be for a period in excess of one
(1) year or for the entire unexpired portion of the Term (as theretofore
extended, if applicable), then Tenant shall have the option to terminate this
lease, effective as of the date specified by Tenant in its notice of
termination; provided, however, that those provisions of this lease which are
designated to cover matters of termination and the period thereafter shall
survive the termination hereof. If the temporary use or occupancy of a portion
only of the Premises shall be so taken and this lease is not terminated by
Tenant pursuant to the foregoing provisions of this Section 17.07, Landlord
shall with due diligence restore the remainder of the Premises to an
architectural unit as nearly like its condition as it existed prior to such
taking as is reasonably feasible. In the event of any such condemnation or
taking, Tenant shall be entitled to appear, claim, prove and receive the portion
of the award for such taking that represents compensation for use or occupancy
of the Premises during the Term and damages for diminution in value or usability
of the remainder of the Premises during the Term (in case of a partial taking),
and Landlord shall be entitled to appear, claim, prove and receive the portion
of the award for such taking that represents compensation for the restoration of
the Premises and the use or occupancy of the Premises after the end of the Term
and damages for diminution in value or usability of the remainder of the
Premises after the Term (in case of a partial taking); provided that, if Tenant
shall terminate this lease as a consequence of such taking, Tenant shall remit
to Landlord so much of the award to Tenant (up to but not in excess of all
thereof) as shall equal (to the extent possible) the discounted present value
(discounted at the Prime Rate per annum as of the date of Tenant's receipt of
such award) of the Rental which would have accrued as to the portion of the
Premises so taken after such termination and during the period of such taking
(to, but not beyond, the end of the Term, as theretofore extended, if
applicable).

                                  ARTICLE 18

                           ASSIGNMENT AND SUBLETTING

                (a)  Except as hereinafter provided, Tenant may not sell,
assign, transfer, or hypothecate this lease or any interest herein or sublet the
Premises or any part thereof without prior written consent of Landlord, except
that Landlord's approval of any proposed sublease shall not be unreasonably
withheld. Landlord hereby consents to any assignment or sublease to any
corporation controlling, assignment or sublease to any corporation controlling,
controlled by,

                                     -28-
<PAGE>

or under common control with Tenant, or to any purchaser of all or substantially
all of the assets of Tenants. The parties agree that in the case of a proposed
sublease, it shall be reasonable for Landlord to withhold its approval if
Landlord determines in good faith that the proposed subtenant is nor financially
creditworthy, or is a medical or dental practice or is a user that will attract
a volume, frequency or type of visitor or employee to the Building which is not
consistent with the standards of a high quality office building or that will
impose an excessive demand or use on the facilities or services of the Building
or whose occupancy of the Premises would not be compatible with Landlord's
interests.

                (b)  If Tenant should desire to either (i) assign this lease or
(ii) sublet the Premises (or any part thereof), and provided that Tenant is not
then in default hereunder, Tenant shall give Landlord written notice at least
ninety (90) but no more than one hundred eighty (180) days in advance of the
date on which Tenant desires to make such assignment or sublease. Landlord shall
then have a period of thirty (30) days following receipt of such notice within
which to notify Tenant in writing that Landlord elects either (i) to permit
Tenant to assign or sublet such space, subject, however, to the subsequent
written approval of the proposed assignee or subtenant by Landlord; or (ii) to
refuse, in Landlord's sole and absolute discretion in the case of an assignment,
or in Landlord's reasonable discretion in the case of a subletting, to consent
to Tenant's assignment or subletting of such space and to continue this lease in
full force and effect as to the entire Premises. If Landlord fails to notify
Tenant in writing of such election within such thirty- (30) day period, Landlord
shall be deemed to have elected option (i) above. In the event that Tenant shall
sublease any portion or portions of the Premises with Landlord's consent (or
deemed consent) pursuant to this subsection 18.01(b), and if any such sublease
or subleases cover any period after the end of the fifth (5th) Lease Year
(herein called "Subject Subleases"), whether one or more, Tenant shall maintain
an account (the "Sublease Account") and shall enter debits and credits in such
Sublease Account and make payments (if any become due) of additional Rental to
Landlord as follows:

                     (i)  The Sublease Account shall be credited with the amount
of all rentals received by Tenant under and pursuant to all Subject Subleases,
including the reasonable value of any specific consideration paid to Tenant for
any such Subject Sublease in addition to "rental" paid thereunder.

                     (ii) The Sublease Account shall be debited with the amount
of all Rental paid by Tenant under this lease for or attributable to the
Rentable Area covered by each Subject Sublease during the term of such Subject
Sublease (except any additional Rental paid by Tenant to Landlord pursuant to
this subsection 18.01(b)).

                     (iii)  The Sublease Account shall be debited with all
direct costs and expenses incurred by Tenant in connection with entering into,
performing its obligations under and enforcing each such Subject Sublease,
including, without limitation, brokerage fees and commissions, legal fees,
accounting fees, costs and expenses of renovating or altering and maintaining
the portion of the Premises occupied or to be occupied or used by the subtenant
under any such Subject Sublease to comply with the requirements of such Subject
Sublease, costs and expenses of electricity, heating and air-conditioning
provided by Tenant to the subleased areas covered by such Subject Subleases
(determined and allocated on a pro rata per square foot of Rentable Area basis
with reference to the costs and expenses incurred by Tenant

                                     -29-
<PAGE>

for electricity, heating and air-conditioning in the entire Premises), and (if
applicable) costs and expenses of janitorial service, cleaning or other services
provided by Tenant to the subleased areas covered by such Subject Subleases,
provided there is no duplication of any such costs or expenses otherwise debited
to such Sublease Account.

                     (iv) If one or more Subject Subleases are entered into
prior to the end of the fifth (5th) Lease Year, and if the aggregate credits to
the Sublease Account as of the end of the fifth (5th) Lease Year shall exceed
the aggregate debits to such Sublease Account as of such date, the Sublease
Account shall be debited on such date with the amount of such excess (so as to
cause the aggregate debits to equal the aggregate credits as of such date). The
allocation of rental from Subject Subleases entered into prior to the end of the
fifth (5th) Lease Year shall be commercially reasonable.

                     (v)  If at the end of any month commencing after the end of
the fifth (5th) Lease Year the aggregate credits to the Sublease Account shall
exceed the aggregate debits to the Sublease Account as of such date, Tenant
shall, within ten (10) days thereafter, pay to Landlord, as additional Rental
under this lease, an amount equal to fifty percent (50%) of such excess; and
incident to such payment the Sublease Account shall be debited with an amount
equal to one hundred percent (100%) of such excess.

                (c)  If Tenant notifies Landlord of Tenant's desire to assign
this lease or sublet the Premises, more than once in any twelve (12) month
period, Tenant shall pay to Landlord as additional Rental with the next due
monthly Rental the actual legal fees, if any, for outside counsel, incurred by
Landlord to have such proposed sublease or assignment reviewed and evaluated. No
assignment or subletting by Tenant shall relieve Tenant of Tenant's obligations
under this lease. Any attempted assignment or subletting by Tenant in violation
of the terms and provisions of this Section 18.01 shall be void.

        Section 18.02.  Landlord may sell, transfer, assign, and convey, all or
        --------------
any part of the Building and any and all of its rights under this lease, and in
the event Landlord assigns its rights under this lease, Landlord shall be
released from any further obligations hereunder, and Tenant agrees to look
solely to Landlord's successor in interest for performance of such obligations;
provided that, notwithstanding any such assignment by Landlord of its rights
under this lease, Landlord shall nevertheless be and remain liable and
responsible for performance of all Landlord's covenants and agreements contained
and set forth in Section 25.04 of this lease for and during the entire term of
this lease and any extension of such term herein provided for.

                                  ARTICLE 19

                                INDEMNIFICATION

     Tenant waives all claim against Landlord for damage to any property, or
injury to, or death of any person in, upon or about the Building, the Premises,
or the parking facilities in the Building arising at any time and from any cause
other than (i) by reason of the willful misconduct of Landlord its agents or
employees, or (ii) in the case of injury to or death of any person, by reason of
the negligence of Landlord, its agents or employees; and Tenant shall indemnify
Landlord and shall hold Landlord harmless from any damage to property or injury
to,

                                     -30-
<PAGE>

or death of any person arising from the use of the Building, the Premises, or
the parking facilities by Tenant or its agents, employees, representatives,
contractors or invitees, except such as is caused (i) by the willful misconduct
of Landlord, its agents or employees or (ii) in the case of injury to or death
of any person , by reason of the negligence of Landlord or employees. Without
limiting the generality of the foregoing, Landlord shall not be liable for any
injury or damage to persons or property resulting form fire, explosion, falling
plaster, steam, gas, electricity, water, rain, flood, snow, or leaks from any
part of the Premises or from the pipes, appliance, equipment, plumbing works,
roof, or subsurface of any floor or ceiling, or from the street or any other
place, or by dampness or any other cause whatsoever, unless caused (i) by
Landlord's willful misconduct or (ii) in the case of injury to or death of any
person, by reason of the negligence of Landlord, its agents or employees.
Landlord shall not be liable for any such damage caused by other tenants or
persons in the Building or by occupants of adjacent property thereto, or by the
public, or caused by any private, public, or quasi-public construction or other
work, including, but not limited to, any construction modification, or operation
of underground, ground-level or above-ground pedestrian tunnels, bridges,
walkways, or similar items. Tenant's foregoing indemnity obligation shall
include reasonable attorneys' fees, investigation costs, and expenses incurred
by Landlord from the first notice that any claim or demand has been made or may
be made, but only to the extent such fees, costs and expenses are not covered by
Landlord's insurance. The provisions of this Article 19 shall survive the
termination of this lease with respect to any damage, injury, or death occurring
before such termination. If Landlord is made a party to any litigation commenced
by or against Tenant or relating to this lease or to the Premises, and provided
that in any such litigation Landlord is not finally adjudicated to be at fault,
then Tenant shall pay all costs and expenses, including reasonable attorneys'
fees and court costs, incurred by or imposed upon Landlord because of any such
litigation, but only to the extent such fees, costs and expenses are not covered
by Landlords insurance, and the amount of all such costs and expenses, including
reasonable attorneys' fees and court costs, shall be a demand obligation owing
by Tenant to Landlord. Tenant shall have the right, at Tenant's sole cost and
expense, to participate in the defense of any such action or proceeding brought
in connection with any claim against Landlord by a third party and to
participate in the negotiations for the settlement thereof. Tenant may retain
attorneys for such purposes. If Landlord agrees to a settlement or compromise of
a claim with respect to which Tenant has agreed to indemnify Landlord under this
Article 19, which settlement would require Tenant to suffer any loss, damage or
injury, without Tenant's specific prior written consent to and approval of such
settlement or compromise, Tenant shall be released from its indemnity obligation
with respect to such claim.

                                  ARTICLE 20

                           SURRENDER OF THE PREMISES


        Section 20.01.   Upon the expiration of the Term or other termination of
        --------------
this lease for any cause whatsoever, Tenant shall peacefully vacate the Premises
in as good order and condition as the same were at the beginning of the Term or
may thereafter have been improved by Landlord or Tenant, reasonable use and wear
thereof and damage to the Premises or the leasehold improvements by fire or
other casualty or condemnation only excepted, provided that at Tenant's election
and at Tenant's cost and expense, Tenant may remove any decorative

                                     -31-
<PAGE>

improvements (such as chandeliers, built-in cabinets, etc.) installed by Tenant
in the Premises and Tenant shall repair any damage caused by such removal.
Should Tenant continue to hold the Premises after the termination of this lease,
whether the termination occurs by lapse of time or otherwise, such holding over,
unless otherwise agreed to by Landlord in writing, shall constitute and be
construed as a tenancy at will at a daily Rental equal to one-thirtieth (1/30)
of an amount equal to the monthly Fair Market Value Rate (as defined in Article
32) for the first thirty (30) days, and from and after thirty (30) days after
this lease has been terminated, at a daily Rental equal to 1/30th of an amount
equal to two times the monthly Fair Market Value Rate (as defined in Article
32), in each case, times the number of square feet of Rentable Area in the
Premises as of the date of termination and subject to all of the other terms set
forth herein except any right to renew this lease, but the foregoing shall not
constitute a consent by Landlord to such holding over and shall not prevent
Landlord from exercising any of its remedies under this lease or applicable law
by reason of such holding over. Tenant shall be liable to Landlord for all
damage which Landlord suffers because of any holding over by Tenant, and Tenant
shall indemnify Landlord against all claims made by any other tenant or
prospective tenant against Landlord resulting from delay by Landlord in
delivering possession of the Premises to such other tenant or prospective
tenant.

        Section 20.02.
        --------------

                (a)  Tenant shall remove, at Tenant's expense, all of its
furniture, furnishings, personal property, and movable trade fixtures by the
Expiration Date, and shall promptly repair all damage done to the Premises or
the Building by such removal. Any items not so removed at the later of the
Expiration Date or the expiration of any period during which Tenant holds over
in the possession of the Premises as described in Section 20.01, shall be deemed
abandoned and shall thereupon become the property of Landlord.

                (b)  Except as provided in Section 20.02(a) and Section 20.01,
Tenant shall not remove any alteration made by Tenant or any of the leasehold
improvements in the Premises at the expiration of the Term without Landlord's
consent.

                                  ARTICLE 21

                             ESTOPPEL CERTIFICATES

     Tenant agrees to furnish no later than fifteen (15) days after a request
therefor by Landlord, any ground lessor, or the holder of any deed of trust or
mortgage covering the Building, the Land, or any interest of Landlord therein or
any purchaser of Landlord's interest, a certificate signed by Tenant certifying
(to the extent same is true) that this lease is in full force and effect and
unmodified; that the Term has commenced and the full Rental is then accruing
hereunder; that Tenant has accepted possession of the Premises and that any
improvements required by the terms of this lease to be made by Landlord have
been completed to the satisfaction of Tenant; that no Rental under this lease
has been paid more than thirty (30) days in advance of its due date; that the
address for notices to be sent to Tenant is as set forth in this lease (or has
been changed by notice duly given and is as set forth in the certificate); that
Tenant, as of the date of such certificate, has no knowledge of any charge,
lien, or claim of offset under this lease or otherwise against Rentals or other
charges due or to become due hereunder; that

                                     -32-
<PAGE>

Tenant has no knowledge of any default by Landlord then existing under this
lease; and such other matters as may be reasonably requested by Landlord or any
such ground lessor, holder of such deed of trust or mortgage or purchaser. If
Tenant is unable to so certify as to one or more of the foregoing items, Tenant
shall specify its reason therefor in writing. Any such certificate may be relied
upon by any prospective purchaser, ground lessor, mortgagee, or any beneficiary
under any deed of trust on the Building or the Land or any part thereof.
Landlord agrees to furnish periodically, when reasonably requested in writing by
Tenant, certificates signed by Landlord containing substantially the same
information as described above.

                                  ARTICLE 22

                                 SUBORDINATION


        Section 22.01.  Landlord warrants and represents that there is no deed
        --------------
of trust or mortgage in existence as of the date hereof covering or burdening
the Building and/or the Land. This lease shall be subject and subordinate to any
future first deeds of trust, first mortgages or other first security instruments
(collectively, "Superior Instruments") which may from time to time during the
Term cover the Building and/or the Land, or any interest of Landlord therein,
and to any advances made on the security thereof, and to any refinancings,
increases, renewals, modifications, consolidations, replacements, and extensions
of any such future Superior Instruments, provided that the holder of any such
Superior Instrument has executed, acknowledged and delivered a non-disturbance
agreement whereby such holder agrees not to diminish or interfere with Tenant's
possession of the Premises nor to disturb Tenant's occupancy of the Premises
except in accordance with Article 23 hereof. Upon execution and delivery of such
non-disturbance agreement, this Section 22.01 shall be self-operative and no
further instrument shall be required to effect such subordination of this lease.
Upon demand, however, Tenant shall execute, acknowledge, and deliver to Landlord
any further instruments and certificates evidencing such subordination as
Landlord or the holder of any Superior Instrument may reasonably request, and
Tenant hereby irrevocably appoints Landlord as Tenant's agent and attorney-in-
fact, for the purpose of executing, acknowledging, and delivering any such
instruments and certificates.

        Section 22.02.   Notwithstanding the generality or the foregoing
        --------------
provisions of Section 22.01 hereof, any holder of a Superior Instrument shall
have the right, unilaterally, at any time, to subordinate fully or partially any
such Superior Instrument to this lease. Upon request, Tenant shall execute an
instrument confirming any such full or partial subordination by any holder of a
Superior Instrument. At any time, before or after the institution of any
proceedings for the foreclosure of any Superior Instrument, or sale of the
Building and/or under any Superior Instrument, or upon the termination of any
ground lease, Tenant shall attorn to such purchaser upon any such sale or the
grantee under any deed in lieu of such foreclosure or to any ground lessor in
the event of a termination of a ground lease, as the case may be, and shall
recognize such ground purchaser, grantee or ground lessor, as the case may be,
as Landlord under this lease. Tenant hereby waives the right, if any, to elect
to terminate this lease or to surrender possession of the Premises in the event
of the judicial or non-judicial foreclosure of any deed of trust, mortgage, or
security agreement (or any transfer in lieu thereof) or termination of a ground
lease, subject to Tenant's right to terminate this lease under any provision of
any other Article

                                     -33-
<PAGE>

hereof upon the terms, conditions and contingencies therein provided. The
foregoing agreement of Tenant to attorn shall survive any such foreclosure sale,
trustee's sale, or conveyance in lieu thereof, or termination of a ground lease.
Tenant shall, upon demand at any time, before or after any such foreclosure
sale, trustee's sale, or conveyance in lieu thereof, or termination of a ground
lease, execute, acknowledge, and deliver to Landlord's mortgagee or any
successor thereof or any then owner of the Building or to the ground lessor (as
the case may be), any written instruments and certificates evidencing such
attornment as such mortgagee, successor, owner or ground lessor may reasonably
require, and Tenant hereby irrevocably appoints Landlord's mortgagee or ground
lessor (as the case may be) as Tenant's agent and attorney-in-fact for the
purpose of executing, acknowledging, and delivering any such instruments and
certificates.

        Section 22.03.   Should any ground lease be terminated, or any deed of
        --------------
trust, mortgage, or security instrument be foreclosed, the liability of the
ground lessor, mortgagee, trustee, or purchaser, as the case may be, as
"Landlord" hereunder, shall exist only with respect to the acts or omissions of
such person or entity occurring while it was the owner of the Land and/or
Building. Further, Tenant agrees that any such ground lessor, mortgagee,
trustee, or purchaser shall not be liable for (i) any Rental paid more than
thirty (30) days in advance of its due date (other than the one monthly
installment of Annual Rental paid in advance incident to the execution of this
lease); (ii) any amendment or modification of this lease without the prior
written approval of such ground lessor, mortgagee, trustee, or purchaser (but
only if Tenant had been notified in writing of the existence of the ground
lease, mortgage, deed of trust or sale, as the case may be, prior to the making
of such amendment or modification of this lease); or (iii) any default by or any
claim against any prior Landlord; provided that nothing in this Section is
intended or shall be construed to waive any right of Tenant to terminate this
lease by reason of a default by such prior Landlord in accordance with Section
25.05, or to cure any default by such prior Landlord and deduct the cost thereof
from Rental accruing hereunder in accordance with Section 25.05, either prior to
or after termination of such ground lease or foreclosure of such deed of trust,
mortgage or security instrument.

                                  ARTICLE 23

                             DEFAULT AND REMEDIES

        Section 23.01.   The occurrence of any one or more of the following
        --------------
events shall constitute an event of default under this lease: (a) if Tenant
shall fail to pay any Rental or other sums payable by Tenant hereunder as and
when such Rental or other sums become due and payable and such failure shall
continue for more than five (5) days after notice; (b) if Tenant shall fail to
perform or observe any covenant or obligation hereunder or any of the Rules and
Regulations and such failure shall continue for more than ten (10) days after
notice; or, if such failure cannot be corrected within such ten- (10) day
period, if Tenant does not commence to correct same within said ten- (10) day
period and thereafter diligently prosecute the correction of same to completion;
(c) if any petition is filed by or against Tenant under any section or chapter
of the present, or any future Federal Bankruptcy Code or under any similar law
or statute of the United States or any state thereof (which, in the case of an
involuntary proceeding, is not permanently discharged, dismissed, stayed, or
vacated, as the case may be, within sixty (60) days of its commencement), or if
any order for relief shall be entered against Tenant or any guarantor of
Tenant's obligations under this lease in proceedings filed under any section or
chapter of the

                                     -34-
<PAGE>

present or any future Federal Bankruptcy Code or under any similar law or
statute of the United States or any state thereof; (d) if Tenant becomes
insolvent or makes a transfer in fraud of creditors; (e) if Tenant makes an
assignment for the benefit of creditors; (f) if a receiver, custodian, or
trustee is appointed for Tenant or for any of the assets of Tenant, which
appointment is not vacated within sixty (60) days of the date of such
appointment or (g) if Tenant shall fail to pay to Landlord when due any Rental
becoming payable hereunder (without regard to any grace period otherwise allowed
by this Section 23.01) during any twelve- (12) month period during the Term
after Landlord has given Tenant written notice of failure to pay other
installments or amounts of Rental when due (prior to making of such payment by
Tenant) on at least two (2) prior separate occasions during such twelve- (12)
month period.

        Section 23.02.   If an event of default occurs, then at any time
        --------------
thereafter while Tenant remains in default, Landlord may do any one or more of
the following:

                (a)  Terminate this lease on three (3) days notice to Tenant, in
which event Tenant shall immediately surrender the Premises to Landlord. If
Tenant fails to do so, Landlord may, without notice and without prejudice to any
other remedy Landlord may have, enter upon and take possession of the Premises
and expel or remove Tenant and its effects without being liable to prosecution
or any claim for damages therefor; and Tenant shall indemnify Landlord for all
loss and damage which Landlord may suffer by reason of such termination, whether
through inability to relet the Premises or otherwise, including any loss of
Rental for the remainder of the Term. In the event of such termination, Landlord
shall exercise reasonable diligence and effort to relet the Premises for the
remainder of the Term.

                (b)  Enter upon and take possession of the Premises as Tenant's
agent, terminating this lease and without being liable to prosecution or any
claim for damages therefor, and Landlord may relet the Premises as Tenant's
agent and receive the Rental therefor, in which event Tenant shall pay to
Landlord on demand any and all costs of releasing, renovating, repairing, and
altering the Premises (including but not limited to advertising costs,
commissions, finders fees and other similar costs) for a new tenant or tenants
and any deficiency that may arise by reason of such reletting.

                (c)  Do whatever Tenant is obligated to do under this lease and
enter the Premises without, being liable to prosecution or any claim for damages
therefor to accomplish this purpose. Tenant shall reimburse Landlord immediately
upon demand for any expenses which Landlord incurs in thus effecting compliance
with this lease on Tenant's behalf, and Landlord shall not be liable for any
damages suffered by Tenant from such action, whether caused by the negligence of
Landlord or otherwise.

        Section 23.03.  No act or thing done by Landlord or its agents during
        --------------
the Term shall constitute an acceptance of an attempted surrender of the
Premises, and no agreement to accept a surrender of the Premises shall be valid
unless made in writing and signed by Landlord. No re-entry or taking possession
of the Premises by Landlord shall constitute an election by Landlord to
terminate this lease, unless a written notice of such intention is given to
Tenant. Notwithstanding any such reletting or re-entry or taking possession,
Landlord may at any time thereafter terminate this lease for a previous default.
Landlord's acceptance of Rental following an event of default hereunder shall
not be construed as a waiver of such event of default. No

                                     -35-
<PAGE>

waiver by Landlord of any breach of this lease shall constitute a waiver of any
other violation or breach of any of the terms hereof. Forbearance by Landlord to
enforce one or more of the remedies herein provided upon a breach hereof shall
not constitute a waiver of any other breach of the lease.

        Section 23.04.   No provision of this lease shall be deemed to have been
        --------------
waived by Landlord or Tenant unless such waiver is in writing and signed by such
party. Nor shall any custom or practice which may evolve between the parties in
the administration of the terms of this lease be construed to waive or lessen
Landlord's or Tenant's right to insist upon strict performance of the terms of
this lease. The rights granted to Landlord and Tenant in this lease shall be
cumulative of every other right or remedy which Landlord or Tenant may otherwise
have at law or in equity or by statute, and the exercise of one or more rights
or remedies shall not prejudice or impair the concurrent or subsequent exercise
of other rights or remedies.

                                  ARTICLE 24

                               WAIVER BY TENANT

     To the extent permitted by applicable law, Tenant waives for itself and all
claiming by, through, and under it, including creditors of all kinds, any right
and privilege which it or any of them may have under any present or future
constitution, statute, or rule of law to redeem the Premises or to have a
continuance of this lease for the Term after termination of Tenant's right of
occupancy by order or judgment of any court or by any legal process or writ,
under the terms of this lease, or after the termination of the Term as herein
provided.

                                  ARTICLE 25

                      ADDITIONAL COVENANTS AND AGREEMENTS

        Section 25.01.   The Land is covered by a Lease Agreement dated June 8,
        --------------
1982, between The Government of the United States, as "Lessor," and Landlord
herein, as "Lessee," as amended by a First Amendment to Lease Agreement dated
February 22, 1985, between such "Lessor" and "Lessee" (said Lease Agreement as
thus amended being herein called the "Ground Lease"). Landlord warrants and
represents that the Ground Lease is in full force and effect, that no default or
condition or circumstance which by the giving of notice and expiration of time
without cure would constitute a default by the "Lessee" under the terms of the
Ground Lease exists, and that Landlord as "Lessee" under the Ground Lease has
fully performed all obligations, duties and agreements of the "Lessee" which
have accrued or are required to be performed to date under the terms of the
Ground Lease.

        Section 25.02.   [INTENTIONALLY DELETED)
        --------------

        Section 25.03.   Landlord agrees to endeavor in good faith to obtain,
        --------------
and to deliver to Tenant, an executed, acknowledged nondisturbance agreement
from the "Lessor" under the Ground Lease, whereby such "Lessor" agrees not to
diminish or interfere with Tenant's possession of the Premises, for any reason
during the Term, unless and until this lease shall be terminated under the
provisions hereof for default by Tenant, provided, however, that if Landlord

                                     -36-
<PAGE>

is unable to obtain such nondisturbance agreement, this lease shall continue in
full force and effect, and the rights and obligations hereunder shall not be
affected.

        Section 25.04.   If a nondisturbance agreement from the "Lessor" under
        --------------
the Ground Lease as described in Section 25.03 is not obtained and furnished to
Tenant then (a) Landlord covenants and agrees that it will at all times during
the Term comply with and perform all obligations, duties and agreements of the
"Lessee" under and in connection with the Ground Lease and will maintain such
Ground Lease in full force and effect throughout the Term hereof, at Landlord's
cost and expense; (b) Landlord agrees to indemnify and save and hold Tenant
harmless from any loss, cost, expense, claim or liability whatsoever (including,
but without limitation, indirect and consequential damages, if any) which may be
suffered or incurred by Tenant as a result of any failure by Landlord to comply
with or perform its covenants and agreements under the provisions of clause (a)
of this Section 25.04; and (c) notwithstanding anything herein contained to the
contrary, Tenant shall have no obligation to attorn to the Ground Lessor in the
event the Ground Lease shall be terminated and the provisions of Section 22.02
of this Lease requiring Tenant to attorn to the Ground Lessor under the Ground
Lease and all references in Section 22.02 and 22.03 to the Ground Lessor and the
Ground Lease shall be deleted therefrom and shall be of no force or effect
whatsoever.

        Section 25.05.   If at any time or times Landlord shall be in default in
        --------------
the performance or observance of any of its covenants, agreements or
undertakings in this lease, and a court of competent jurisdiction has entered a
final judgment or decree not subject to appeal declaring Landlord to have
defaulted in the performance of its covenants, agreements or undertakings
hereunder, and if Landlord shall not cure or remedy such default as specified in
the final judgment or decree within thirty (30) days after the final judgment or
decree has been issued by the court and actually received by Landlord, or, if
such default as specified cannot reasonably be cured and remedied within thirty
(30) days, if Landlord shall not commence in good faith to cure and remedy such
default within thirty (30) days after the final judgment or decree has been
issued by the court and actually received by Landlord and continue with due
diligence until such default is cured and remedied, then, in addition to any
other rights or remedies that may be available to Tenant in law or equity:

                (a)  Tenant may terminate this lease by giving written notice of
termination to Landlord at any time thereafter and prior to the time when such
default is fully cured and remedied, in which event the Term of this lease will
end on the date specified in Tenant's notice of termination as if such date were
the date originally defined herein as the Expiration Date; or

                (b)  Tenant may, but shall not be obligated to, take such action
as in Tenant's good faith judgment is reasonably appropriate to cure and remedy
such default by Landlord, and Landlord shall, within ten (10) days after receipt
of demand therefor, pay to Tenant an amount equal to all reasonable costs and
expenses incurred by Tenant in so curing and remedying such default, failing
which Tenant shall be entitled to deduct and withhold the amount of such costs
and expenses, with interest thereon at the Prime Rate per annum from the date of
demand, from the next ensuing installments and payments of Rental becoming due
under this lease and shall not be in default hereunder for so doing. Tenant
shall have no liability for any action or omission taken or omitted in good
faith in connection with curing or remedying any default by Landlord pursuant to
this subsection 25.05(b); and Tenant's action in commencing to effect a

                                     -37-
<PAGE>

cure or remedy with respect to a default by Landlord pursuant to this subsection
25.05(b) shall not waive Tenant's continuing right, at its election, to
terminate this lease for such default pursuant to subsection 25.05(a) above at
any time before such default is fully cured and remedied.

        Section 25.06.  By Executive Order 11966 dated January 19, 1977,
        --------------
Landlord has been designated as a public international organization entitled to
enjoy the privileges, exemptions and immunities conferred by the International
Organizations Immunities Act (22 U.S.C. (S) 288). As authorized by 22 U.S.C.
288a(b), and as a material and essential consideration and inducement for Tenant
to enter into this lease, Landlord hereby expressly waives the immunity of
Landlord and its property and assets, wherever located, and by whomever held
(other than the INTELSAT Space Segment [the "Space Segment"] as described in
Article I(i) of that certain Agreement Relating to the International
Telecommunications Satellite Organization ["INTELSAT"] done at Washington, D.C.
August 420, 1971, and entered into force February 12, 1973), from suit and any
form of judicial process conferred Act or which by said International
Organizations Immunities Act or which might otherwise exist under international
law or otherwise, with respect to any claim, (a "Subject Claim") of Tenant or
its successors or assigns arising under or in connection with this lease or in
connection with any dispute hereunder or by virtue of any default by Landlord
under this lease or any failure or refusal by Landlord to perform or observe any
of its covenants, agreements, undertakings or duties hereunder; and in this
regard Landlord expressly agrees that any United States District Court in the
District of Columbia shall have jurisdiction to entertain suits for and hear and
render judgment on and with respect to any Subject Claim, that service upon
Landlord in any such suit may be effected by service upon the Director General
or acting Director General of Landlord (or their successors in office) in a
manner consistent with the Federal Rules of Civil Procedure. If Tenant after
using reasonable efforts is unable to effect service upon the Director General
or acting Director General (or their successors in office) as provided above,
Tenant may notify Landlord of such inability which notice shall contain a copy
of the complaint or other process or material sought to be served, and five (5)
days after such notice has been delivered to Landlord, Tenant may effect service
upon any officer or executive of Landlord or in any other manner provided in the
Federal Rules of Civil Procedure for effecting service upon a Corporation
organized under the laws of a state of the United States of America. Execution
or any other process provided for by law of the Federal Rules of Civil Procedure
may be levied and enforced upon and against any property or assets of Landlord,
wherever located, and by whomever held other than any part of the Space Segment,
for satisfaction of any final judgment against Landlord rendered in any suit on
or with respect to a Subject Claim.

                                  ARTICLE 26

                             VAN PARKING FACILITY

     Tenant shall have the right to have constructed a parking facility to allow
Tenant to park five (5) vans located adjacent to the ramp leading into the
Building parking garage in the area described in Exhibit H as hereinafter
provided.  Tenant shall submit to Landlord preliminary plans and specifications
for such facility for Landlord's approval, such approval not to be unreasonably
withheld.  If Landlord approves the preliminary plans and specifications, and
provided Tenant receives the approval of any necessary governmental authority,
Landlord shall

                                     -38-
<PAGE>

prepare final plans and specifications consistent with such approved preliminary
plans and specifications, and shall construct such additional parking facility
substantially in accordance with such final plans and specifications. Landlord
shall pay that part of the cost of constructing such additional parking facility
equal to the lesser of (i) 50% of such costs or (ii) Twenty-Five Thousand
Dollars ($25,000.00) and Tenant shall pay the remainder of such costs. During
the Term, Tenant shall maintain and repair the additional parking facility at
Tenant's sole cost and expense, provided, however, that Landlord shall be
responsible for all structural repairs which may be required.

                                  ARTICLE 27

                      ATTORNEYS' FEES AND LEGAL EXPENSES

     In any action or proceeding brought by either party against the other under
this lease, the prevailing party shall be entitled to recover from the other
party reasonable attorneys' fees, investigation costs, and other reasonable
legal expenses and court costs incurred by such party in such action or
proceeding.

                                  ARTICLE 28

                                    NOTICES

        Section 28.01.   Any notice or demand, consent, approval or disapproval,
        --------------
or statement (collectively called "Notices") required or permitted to be given
by the terms and provisions of this lease, or by any law or governmental
regulation, shall be in writing (unless otherwise specified herein) and unless
otherwise required by such law or regulation, shall be personally delivered or
sent by United States mail postage prepaid as registered or certified mail,
return receipt requested. Any Notice shall be addressed to Landlord or Tenant,
as applicable, at its address specified in the Basic Lease Information as said
address may be changed from time to time as hereinafter provided. By giving the
other party at least ten (10) days' prior written notice, either party may, by
Notice given as above provided, designate a different address or addresses for
Notices.

        Section 28.02.   Any Notice shall be deemed given as of the date of
        --------------
delivery as indicated by affidavit in case of personal delivery or by the return
receipt in the case of mailing; and in the event of failure to deliver by reason
of changed address of which no Notice was given or refusal to accept delivery,
as of the date of such failure as indicated by affidavit or on the return
receipt or by notice of postal service, as the case may be.

                                  ARTICLE 29

                                    PARKING

        Section 29.01.   Landlord shall provide or require that any garage
        --------------
operator shall offer to Tenant up to the sum of (i) fifty (50) plus (ii) one (1)
for each additional 1,300 square feet of Rentable Area of the Premises above
73,153 square feet, monthly parking contracts to park an automobile ("Parking
Rights") in the Building garage. Parking Rights shall be on a self-park or

                                     -39-
<PAGE>

attendant parking basis, as determined by the garage operator (whether Landlord
or a third party).

        Section 29.02.   The monthly parking rate for Parking Rights shall be
        --------------
the prevailing rate charged from time to time by the garage operator for similar
monthly parking contracts. Except as otherwise provided herein, contracts for
the Parking Rights shall be with the garage operator and shall contain the same
terms as are usually contained in contracts with other customers of the garage
operator.

        Section 29.03.   If Tenant does not contract for the maximum number of
        --------------
Parking Rights so allocated to it within ninety (90) days after the Commencement
Date, then Tenant's rights to the unused Parking Rights shall expire. However,
in the event there are Parking Rights available not needed by Landlord or any
tenant in the Building, Tenant shall have the right to contract for such Rights
until such time as Landlord requests that Tenant give up such Rights to permit
their use by Landlord or another tenant of the Building. It is, however,
expressly agreed that if the garage operator is Landlord or Landlord's
Affiliate, the monthly parking rate for Parking Rights shall not exceed the
prevailing monthly parking rates in the general area of the Building for
comparable parking facilities; and the terms of the contracts for the Parking
Rights shall be reasonable and not more onerous from the customer's standpoint
than terms customarily contained in monthly parking contracts of other garage
operators in the area of the Building with respect to comparable parking
facilities.

        Section 29.04.   If all or any portion of the parking facilities in the
        --------------
Building shall be damaged or rendered unusable by fire or other casualty or any
taking pursuant to eminent domain proceeding (or deed in lieu, thereof), and as
a result thereof Landlord or the garage operator is unable to make available to
Tenant the parking provided for herein, then the number of cars which Tenant
shall be entitled to park hereunder shall be proportionately reduced so that the
number of cars which Tenant may park in the parking garage after the casualty or
condemnation in question shall bear the same ratio to the total number of cars
which can be parked in the parking garage at such time as the number of cars
Tenant had the right to park in the parking garage prior cars to such casualty
or condemnation bore to the aggregate number of cars which could be parked
therein at that time.

                                  ARTICLE 30

                 ROOF ANTENNA AND SATELLITE DISH INSTALLATION

        Section 30.01.   Tenant shall have the right to install at its sole cost
        --------------
and expense microwave and satellite dish systems (the "Communication Systems")
on the roof of the Building and/or the Land, in accordance with the
specifications (the "Communication Systems Specifications") attached hereto as
Exhibit K and at locations shown on Exhibit K, subject to obtaining all
necessary governmental approvals and permits related thereto. In the event that
the Tenant obtains all necessary governmental approvals and permits for the
installation of the Communication Systems, Tenant may then proceed to install
the Communication Systems, at Tenant's expense, in strict compliance with the
specifications previously provided to Landlord and all applicable governmental
requirements. Tenant acknowledges that it has received a copy of the letter from
Landlord to Tenant regarding U.S. Department of State approval of the

                                     -40-
<PAGE>

Communication Systems, which is attached hereto as Exhibit I. The parties agree
that Landlord shall not make any use whatsoever of the Communications Systems of
Tenant.

        Section 30.02.   During the Term, Tenant, at its sole cost and expense
        --------------
shall maintain and repair the Communication Systems, and, if necessary, shall
install shielding material to protect Landlord's antennas and other technical
facilities now or hereafter installed by Landlord. The Communication Systems
shall be covered by Tenant's All-Risk insurance in accordance with Section
15.01(a). Tenant hereby agrees to indemnify and hold Landlord harmless from and
against any loss or injury of any kind or nature whatsoever arising out of the
installation or operation of the Communication Systems, and any damage to the
Building or the Land caused by such Communication Systems or as a result of such
Communication Systems or any casualty thereto shall be repaired by Tenant at
Tenant's expense.

        Section 30.03.   Landlord shall not install or permit the installation
        --------------
of any other antenna on the INTELSAT Headquarters Building and/or the Land, or
any building thereon, that would interfere with Tenant's reception or broadcast
capabilities under the Communication System Specifications.

                                  ARTICLE 31

                              MEMORANDUM OF LEASE

        Section 31.01.   Landlord shall, at the request of Tenant, execute,
        --------------
acknowledge and deliver to Tenant a memorandum of this lease (a "Lease
Memorandum") in recordable form setting forth the date of this lease, the names
of the parties hereto, the Commencement Date and the Expiration Date and
describing the Premises, Tenant's rights to renew this lease and the Land. Said
Lease Memorandum shall not in any circumstances be deemed to modify or to change
any of the provisions of this lease. Tenant may elect, at its sole expense, to
record said Lease Memorandum.

        Section 31.02.   In event that Landlord executes said Lease Memorandum,
        --------------
Tenant shall after the expiration or termination of the Term, at the request of
Landlord, execute, acknowledge and deliver to Landlord a memorandum in
recordable form evidencing the expiration or termination of this lease. Landlord
may elect, at its sole expense, to record said memorandum.

                                  ARTICLE 32

                                RENEWAL OPTIONS

        Section 32.01.   Tenant shall have and is hereby granted one (1) option
        --------------
to renew or extend the Term for an additional period of five (5) years (the
"Renewal Period"). Subject to the provisions of Section 32.03, the renewal
option shall be exercisable by Tenant by giving written notice of the exercise
of such renewal option to Landlord at least one (1) year prior to the expiration
of the initial Term. In the event that Tenant exercises the option to renew this
lease in accordance with the provisions hereof, then the Term shall be extended
accordingly. Except as otherwise expressly provided herein, the Renewal Period
shall be upon the same terms, covenants and conditions as set forth herein with
respect to the immediately preceding portion of

                                     -41-
<PAGE>

the Term. All references in this lease to the Term shall be construed to mean
the initial Term and the Renewal Period, (and if applicable the Contingent,
Renewal Periods as hereinafter defined) unless the context clearly indicates
that another meaning is intended. For purposes of this lease, no distinction is
made between the terms "extend" and "renew," or any variations thereof.

        Section 32.02.
        --------------

                (a)  If Tenant notifies Landlord in writing on or before the
date which is thirty (30) days after the date of execution of this lease that
Tenant elects to exercise its renewal option, the Annual Rental during the
Renewal Period shall equal [redacted text] multiplied by the Rentable Area of
the Premises and there shall be no change in the amount of the Basic Costs Base
Amount.

                (b)  If Tenant notifies Landlord in writing after the date which
is thirty (30) days after the date of execution of this lease but before the
date that is one (1) year prior to the expiration of the initial Term, that
Tenant elects to exercise its renewal option, the Annual Rental for the Premises
payable pursuant to Section 5.01 for each Lease Year during the Renewal Period
shall equal the greater of (i) the sum of (A) [redacted text] multiplied by the
Rentable Area of the Premises plus (B) an amount per square foot of Rentable
Area equal to fifty percent (50%) of the annualized amount of Tenant's
Proportionate Share of Basic Costs Excess for the Fiscal Year ending during the
Lease Year immediately preceding the Renewal Period divided by the number of
square feet of Rentable Area in the Premises during such preceding Lease Year,
or (ii) ninety-five percent (95%) of the Fair Market Value Rate (as defined
below) of the Premises as of the commencement of the Renewal Period multiplied
by the Rentable Area of the Premises, increased during the second and each
succeeding Lease Year of the Renewal Period by the Market Escalation Factor (as
defined below). In the event Annual Rental during the Renewal Period is
determined pursuant to this Section 32.02(b), the Basic Costs Base Amount for
purposes of calculating Basic Costs Excess shall equal the Basic Costs for the
Fiscal Year ending during the Lease Year immediately preceding the Renewal
Period. For purposes of the preceding sentence, and for purposes of all other
determinations of the Fair Market Value Rate pursuant to this lease, the
applicable percentage of the "Fair Market Value Rate" shall be increased each
Lease Year by whatever periodic adjustment or factor ("Market Escalation
Factor"), CPI or otherwise, that would be agreed upon between a landlord and a
tenant entering into a new lease in a comparable building, assuming the same
assumptions set forth in 32.04. The Market Escalation Factor shall be determined
in the same manner and at the same time as the Fair Market Value Rate as
provided in Sections 32.02(b) and 32.04; provided, however, that the Market
Escalation Factor shall not be less than thirty percent (30%) of the CPI
adjustment (or other similar adjustment factor that may be applicable).

                (c)  If Tenant exercises its renewal option after the date which
is thirty (30) days after the date of execution of this lease, within sixty (60)
days after Landlord has received Tenant's notice of election to extend the Term,
Landlord shall send to Tenant a written notice specifying the Fair Market Value
Rate and Market Escalation Factor as determined by Landlord in accordance with
Section 32.04, provided, however, that in no event shall Landlord be required to
specify its determination of the Fair Market Value Rate and Market Escalation
Factor prior to the date which is one (1) year before the expiration of the
Term. Within fifteen (15) days after receipt of such notice from Landlord,
Tenant shall send Landlord a written notice of Tenant's acceptance or challenge
of Landlord's determination of such Fair Market Value Rate and Market

                                     -42-
<PAGE>

Escalation Factor, provided, however, that in the event that Tenant fails to
respond within such fifteen- (15) day period, Tenant shall be deemed to have
accepted Landlord's determination of the Fair Market Value Rate and Market
Escalation Factor. In the event that Tenant challenges Landlord's determination
of the Fair Market Value Rate and Market Escalation Factor and Landlord and
Tenant are not able to agree on such Fair Market Value Rate and Market
Escalation Factor within fifteen (15) days (the "Negotiation Period") after
Tenant notified Landlord of Tenant's initial rejection of Landlord's
determination of such Fair Market Value Rate and Market Escalation Factor, then
Landlord and Tenant shall each, within fifteen (15) days after the expiration of
the Negotiation Period, select an appraiser, each of whom shall be a District of
Columbia-licensed real estate broker or a MAI-certified real estate appraiser
with ten years experience in the District of Columbia office market, who shall
determine the Fair Market Value Rate and Market Escalation Factor in accordance
with Section 32.04. The appraisers shall be instructed to complete the appraisal
procedure and to submit their written determinations to Landlord and Tenant
within thirty (30) days after their meeting. In the event that the determination
of the Fair Market Value Rate or Market Escalation Factor, respectively,
submitted by Landlord's appraiser is less than or equal to one hundred ten
percent (110%) of the determination of the Fair Market Value Rate or Market
Escalation Factor, as applicable, submitted by Tenant's appraiser, said Fair
Market Value Rate or Market Escalation Factor shall be the average of such
determinations. If the determination of the Fair Market Value Rate or Market
Escalation Factor, respectively, submitted by Landlord's appraiser is greater
than one hundred ten percent (110%) of the determination of the Fair Market
Value Rate or Market Escalation Factor, as applicable, submitted by Tenant's
appraiser, the appraisers shall, within ten (20) days, appoint a third appraiser
with similar qualifications to make such determination of Fair Market Value Rate
or Market Escalation Factor (or both, as applicable) in accordance with the
foregoing limitations. In the event that the two appraisers cannot agree as to
the selection of the third appraiser within fifteen (15) days after Landlord and
Tenant are notified of the determination of the appraisers, either party may
request that the President of the Washington Board of Realtors appoint the third
appraiser. The third appraiser shall be instructed to complete the appraisal
procedure and to submit a written determination of the Fair Market Value Rate or
Market Escalation Factor (or both, as applicable) to Landlord and Tenant within
thirty (30) days after such appraiser's appointment. The determination which is
neither the highest nor the lowest of the three determinations of such Fair
Market Value Rate or Market Escalation Factor (or both, as applicable) shall be
binding upon Landlord and Tenant as the Fair Market Value Rate or Market
Escalation Factor (or both, as applicable). Landlord and Tenant shall each bear
the costs of their respective appraisers. The expenses of the third appraiser
shall be borne one-half (1/2) by Landlord and one-half (1/2) by Tenant.

        Section 32.03.  The renewal option referred to in Section 32.01 above
        --------------
(and the renewal options for the Contingent Renewal Periods described below) may
not be exercised by Tenant if, at the time of exercising such option(s), (i)
this lease shall not be in full force and effect or (ii) an event of default (as
defined in Section 23.01) shall have occurred and shall be continuing. If Tenant
shall fail to exercise the renewal option during the time or in the manner
provided in Section 32.01 for the exercise thereof and at a time when Tenant is
not prohibited from exercising such option under the provisions of this Section
32.03, then, and in such event, such renewal option shall be absolutely void and
of no force and effect.

                                     -43-
<PAGE>

        Section 32.04.   For purposes of this lease, the term "Fair Market Value
        --------------
Rate" means the fair market rental rate per square foot of Rentable Area of the
Premises that would be agreed upon between a landlord and a tenant entering into
a new lease in a comparable building of comparable age, assuming the following:
(A) the landlord and tenant are typically motivated; (B) the landlord and tenant
are well informed and well advised and each is acting in what it considers its
own best interest; (C) the rental is unaffected by concessions, special
financing amounts and/or terms, or unusual services, fees, costs or credits in
connection with the leasing transaction; (D) the Premises are fit for immediate
occupancy and use "as is" and no work is required to be done by landlord and no
work has been carried out thereon by any prior tenant, its subtenant, or their
predecessors in interest during the term which has diminished the rental value
of the Premises; (E) in the event the Premises have been destroyed or damaged by
fire or other casualty, they have been fully restored; (F) the Premises are to
be let with vacant possession and subject to the provisions of this lease for a
five-year term (taking into account the provisions of this lease, including
without limitation Article 6 and Section 8.01 hereof); and (C) market rents then
being charged for comparable space in other similar office buildings in
comparable locations in Washington, D.C.; and (H) the rental determined as the
fair market rental rate as of the commencement of the term of the subject lease
will be subject to being increased during the second and each succeeding year of
the five- (5) year term of the lease by application of the Market Escalation
Factor described below. Likewise, for purposes of this lease, the term "Market
Escalation Factor" shall mean whatever periodic adjustment or factor (Consumer
Price Index ["CPI"] or otherwise) that would be agreed upon by a landlord and a
tenant entering into a new lease in a comparable building of comparable age,
assuming the same assumptions set forth in clauses (A), (B), (C), (D), (E), (F)
and (G) of the first sentence of this Section; provided, however, that the
Market Escalation Factor shall not be less than thirty percent (30%) of the CPI
adjustment (or other similar adjustment factor that may be applicable).

        Section 32.05.
        --------------

                (a)  Provided Tenant has exercise its renewal option and is then
occupying at least seventy-five percent (75%) of the Premises, Landlord shall
notify Tenant on or before the expiration of the twelfth (12th) Lease Year of
the Renewal Period whether Landlord will grant to Tenant three (3) additional
successive options to renew or extend the Term for additional periods of five
(5) years each (the "Contingent Renewal Periods"). In the event Landlord's
notice states that no additional renewal periods will be available, then the
Annual Rental during the last seven and one-half months of the Renewal Period
shall be abated. If Landlord's notice states that Tenant may elect to extend the
Term for the Contingent Renewal Periods, there shall be no such Rental
abatement; and subject to the provisions of Section 32.03, each such renewal
option shall be exercisable by Tenant by giving written notice of the exercise
of such renewal option to Landlord at least one (1) year prior to the expiration
of the Renewal Period in the case of the first such renewal option, and in the
case of the second and third such renewal options, before the expiration of the
immediately preceding Contingent Renewal Period. Except as otherwise expressly
provided herein, each Contingent Renewal Period shall be upon the same terms,
covenants and conditions as set forth herein with respect to the immediately
preceding portion of the Term.

                (b)  The Annual Rental for the Premises payable pursuant to
Section 5.01 for each Lease Year during the first Contingent Renewal Period
shall be equal to the total of (i) the

                                     -44-
<PAGE>

Annual Rental payable by Tenant during the Lease Year immediately preceding such
Contingent Renewal Period divided by the number of square feet of Rentable Area
in the Premises during such preceding Lease Year, multiplied by the number of
square feet of Rentable Area in the Premises during the applicable Lease Year of
the first Contingent Renewal Period, plus (ii) [redacted text] multiplied by the
number of square feet of Rentable Area in the Premises during the applicable
Lease Year of the first Contingent Renewal Period. The Annual Rental for each
Lease Year during the second Contingent Renewal Period shall equal the greater
of (i) the sum of (A) the Annual Rental payable by Tenant during the Lease Year
immediately preceding such second Contingent Renewal Period plus (B) fifty
percent of Tenant's Proportionate Share of Basic Costs Excess payable by Tenant
during the Lease Year immediately preceding such second Contingent Renewal
Period, divided by the number of square feet of Rentable Area in the Premises
during such preceding Lease Year, multiplied by the number of square feet of
Rentable Area in the Premises during the applicable Lease Year of the second
Contingent Renewal Period, or (ii) ninety-five percent (95%) of the Fair Market
Value Rate of the Premises as of the commencement of the second Contingent
Renewal Period multiplied by the Rentable Area of the Premises; increased during
the second and each succeeding Lease Year of the second Contingent Renewal
Period by the Market Escalation Factor. The Annual Rental during the third
Contingent Renewal Period shall equal the greater of (i) the sum of (A) the
Annual Rental Payable by Tenant during the Lease Year immediately preceding such
third Contingent Renewal Period plus (B) fifty percent (50%) of Tenant's
Proportionate Share of Basic Costs Excess payable by Tenant during the Lease
Year immediately preceding such third Contingent Renewal Period, divided by the
number of square feet of Rentable Area in the Premises during such preceding
Lease Year, multiplied by the number of square feet of Rentable Area in the
Premises during the applicable Lease Year of the Third Contingent Renewal
Period, or (ii) ninety-five percent (95%) of the Fair Market Value Rate of the
Premises as of the commencement of the third Contingent Renewal Period
multiplied by the, Rentable Area of the Premises, increased during the second
and each succeeding Lease Year of the third Contingent Renewal Period by the
Market Escalation Factor. The Basic Cost Base Amount for purposes of calculating
Basic Costs Excess for the First Contingent Renewal Period shall be equal to the
Basic Cost Base Amount for the initial Renewal Period. The Basic Costs Base
Amount for purposes of calculating Basic Costs Excess during the second or third
Contingent Renewal Period shall be equal to the Basic Costs for the Fiscal year
ending during the Lease Year immediately preceding such particular Contingent
Renewal Period.

                (c)  In the case of the second and third Contingent Renewal
Periods, Landlord shall within sixty (60) days after Landlord has received
Tenant's notice of election to extend the Term, send to Tenant a written notice
specifying the Fair Market Value Rate as determined in accordance with Section
32.04, provided, however, that in no event shall Landlord be required to specify
its determination of the Fair Market Value Rate prior to the date which is one
(1) year before the expiration of the first or second Contingent Renewal Period,
as the case may be. Except where the context indicates otherwise, the provisions
of Sections 32.02, 32.03 and 32.04 shall apply equally to this Section 32.05.

                                     -45-
<PAGE>

                                  ARTICLE 33

                               EXPANSION OPTION

        Section 33.01.  Subject to the terms and conditions hereinafter set
        --------------
forth and provided that the lease is in full force and effect and no event of
default shall have occurred which shall be continuing, Tenant shall have the
option to lease additional space in the Building (the "Expansion Space") as
follows. Tenant shall have the option (the "Expansion Option") to lease the
space on level 6 of Pod P described in Exhibit J hereto as hereinafter provided.
The Expansion Option shall be exercisable by Tenant upon notice to Landlord
given within six (6) months after the date of execution of this lease. If Tenant
so exercises its Expansion Option as herein provided, such space shall be added
to and constitute a part of the premises, and except as expressly otherwise
hereinafter provided, subject to all the terms and conditions of this lease. If
Tenant delivers to Landlord the drawings, plans, specifications, and other
detailed information which Tenant is required to submit to Landlord in
accordance with Article 2.02 of Exhibit C, if applicable, containing all
information required by Landlord to construct the Base Building Work for the
Expansion Space, the Commencement Date, Expiration Date and free rent period as
to the Expansion Space shall be the same as those for the initial Premises. If
such drawings, plans, specifications, and other detailed information for the
Expansion Space are not delivered by the respective dates specified in Article
2.02 of Exhibit C, if applicable, (i) the delivery date by Landlord of the
Expansion Space with the Base Building Work substantially completed shall have
no effect upon the determination of the Commencement Date for the initial
Premises; (ii) the Commencement Date and commencement of the seven-month free-
rent period for the Expansion Space shall be the earlier of (A) seven and one-
half (7 1/2) months after the date on which Landlord delivers the Expansion
Space to Tenant with the Base Building Work substantially completed, (B) the
date of Tenant's occupancy of the Expansion Space for the conduct of its normal
business operations, or (C) fifteen (15) days after (1) Tenant Build-out for the
Expansion Space is substantially completed, and (2) the Communication Systems
have been installed on the Building and Land, so as to permit Tenant to occupy
the Expansion Space (and the initial Premises) and conduct its normal business
operations therein, it being stipulated that Tenant agrees, subject to delay by
force majeure as defined in Section 2.01(b), to exercise reasonable diligence to
complete and install such Tenant Build-out and Communication Systems after
Tenant is afforded access to the Land, Building, Premises and Expansion Space
for such purpose; (iii) delays by Tenant as specified in Articles 6 and 7 of
Exhibit C with respect to the Expansion Space shall operate to accelerate
Tenant's obligation to pay rental for the Expansion Space; and (iv) The
Expiration Date for the Expansion Space shall coincide with the Expiration Date
of the initial Premises.

        Section 33.02.   Landlord shall construct in the Expansion Space the
        --------------
Base Building Work described in Exhibit C-1 and Landlord shall have no
obligation to make any other alterations, decorations, additions or improvements
in or to the Expansion Space.

                                  ARTICLE 34

                                 MISCELLANEOUS

        Section 34.01.   [INTENTIONALLY DELETED]
        --------------

                                     -46-
<PAGE>

        Section 34.02.   Landlord recognizes Shannon & Luchs Company (the
        --------------
"Broker") and Julien J. Studley Co., Inc. (the "Co-operating Broker") as the
sole brokers procuring this lease. Landlord shall pay the Broker a commission
therefor pursuant to a separate agreement between the Broker and Landlord, and
the Broker shall pay a portion of such commission to the Co-operating Broker.
Except for the Broker and the Co-operating Broker, Landlord and Tenant each
represent and warrant that it has not entered into any agreement with, nor
otherwise had any dealings with, any other broker or agent in connection with
the negotiation or execution of this lease which could form the basis of any
claim by any such broker or agent for a brokerage fee or commission, finder's
fee, or any other compensation of any kind or nature in connection herewith, and
Landlord and Tenant each agree to indemnify and hold the other harmless from any
costs (including, but not limited to, court costs, investigation costs, and
attorneys' fees), expenses, or liability for commissions or other compensation
claimed by any broker or agent with respect to this lease which arise out of any
agreement or dealings, or alleged agreement or dealings, between such party and
any such agent or broker.

        Section 34.03.   As used herein, "business days" means Monday through
        --------------
Friday (except holidays); "normal business hours" means 8:00 a.m. to 6:00 p.m.
on business days; and "holidays" means those holidays other than Veterans Day
designated as national holidays by the government of the United States and the
Friday following Thanksgiving Day.

        Section 34.04.   Every agreement contained in this lease is, and shall
        --------------
be construed as, a separate and independent agreement. If any term of this lease
or the application thereof to any person or circumstances shall be invalid and
unenforceable, the remainder of this lease, or the application of such term to
persons or circumstances other than those as to which it is invalid or
unenforceable, shall not be affected.

        Section 34.05.   There shall be no merger of this lease or of the
        --------------
leasehold estate hereby created with the fee estate in the Premises or any part
thereof by reason of the fact that the same person may acquire or hold, directly
or indirectly, this lease or the leasehold estate hereby created or any interest
in this lease or in such leasehold estate as well as the fee estate in the
Premises or any interest in such fee estate. In the event of a voluntary or
other surrender of this lease, or a mutual cancellation hereof, Landlord may, at
its option, terminate all subleases, or treat such surrender or cancellation as
an assignment of such subleases.

        Section 34.06.   [Intentionally Deleted].
        --------------

        Section 34.07.   Whenever a period of time is herein prescribed for
        --------------
action to be taken by Landlord, Landlord shall not be liable or responsible for,
and there shall be excluded from the computation for any such period of time,
any delays due to "force majeure" as such term is defined in Section 2.01(b)
other than Landlord's obligations with respect to insurance as provided in
Article 15 or Landlord's obligation to make timely payment of all amounts
becoming due from Landlord to Tenant hereunder. Likewise, whenever a period of
time is herein prescribed for action to be taken by Tenant, Tenant shall not be
liable or responsible for, and there shall be excluded from the computation for
any such period of time, any delays due to "force majeure" as such term is
defined in Section 2.01(b), other than Tenant's obligations with respect to
insurance as provided in Article 15, Tenant's obligation to timely pay Rental,
and Tenant's obligation to comply with all time requirements specified in
Exhibit C. In addition, no

                                     -47-
<PAGE>

force majeure circumstance shall operate to (i) extend the seven and one-half
(7 1/2) month period contained in clause (i) of Section 2.01(a), or (ii) extend
the date April 1, 1989, or the date April 1, 1990, contained in Section 3.01 or
(iii) extend the ten- (10) day period contained in Section 8.04.

        Section 34.08.   The article headings contained in this lease are for
        --------------
convenience only and shall not enlarge or limit the scope or meaning of the
various and several articles hereof.  Words of any gender used in this lease
shall include any other gender, and words in the singular number shall be held
to include the plural, unless the context otherwise requires.

        Section 34.09.   If there be more than one Tenant, the obligations
        --------------
hereunder imposed upon Tenant shall be joint and several, and all agreements and
covenants herein contained shall be binding upon the respective heirs, personal
representatives, successors, and, to the extent permitted under this lease,
assigns of the parties hereto.

        Section 34.10.   Neither Landlord nor Landlord's agents or brokers have
        --------------
made any representations or promises with respect to the Premises or the
Building except as herein expressly set forth and all reliance with respect to
any representations or promises is based solely on those contained herein. No
rights, easements, or licenses are acquired by Tenant under this lease by
implication or otherwise except as expressly set forth in this lease.

        Section 34.11.   This lease sets forth the entire agreement between the
        --------------
parties and cancels all prior negotiations, arrangements, brochures, agreements,
and understandings, if any, between Landlord and Tenant regarding the subject
matter of this lease. No amendment or modification of this lease shall be
binding or valid unless expressed in a writing executed by both parties hereto.

        Section 34.12.   The submission of this lease to Tenant shall not be
        --------------
construed as an offer, nor shall Tenant have any rights with respect thereto
unless Landlord executes a copy of this lease and delivers the same to Tenant.

        Section 34.13.   Each of the persons executing this lease on behalf of
        --------------
Tenant represents and warrants that Tenant has complied with all applicable
laws, rules, and governmental regulations relative to its right to do business
in the District of Columbia, that such entity has the full right and authority
to enter into this lease, and that all persons signing on behalf of the Tenant
were authorized to do so by any and all necessary or appropriate corporate or
partnership actions.

        Section 34.14.   Each of the persons executing this lease on behalf of
        --------------
Landlord and/or the general partner of Landlord represents and warrants that
Landlord has complied with all applicable laws, rules and governmental
regulations relative to its right to do business in the District of Columbia,
that such entity has the full right and authority to enter into this lease, and
that all persons signing on behalf of Landlord were authorized to do so by any
and all necessary or appropriate actions.

        Section 34.15. If, in connection with obtaining debt or equity financing
        --------------
for the Building (including a sale/ leaseback) any lender, investor or ground
lessor shall request reasonable modifications to this lease as a condition to
such financing, Tenant will consent

                                     -48-
<PAGE>

thereto if in Tenant's sole good faith determination such modifications do not
increase the obligations of Tenant hereunder or adversely affect the leasehold
interest hereby created, Tenant's use and enjoyment of the Premises or any other
right of Tenant granted hereunder.

        Section 34.16.   This lease shall be governed by and construed under the
        --------------
laws of the District of Columbia. Any action brought to enforce or interpret
this lease shall be brought in the court of appropriate jurisdiction in the
District of Columbia. Should any provision of this lease require judicial
interpretation, it is agreed that the court interpreting or considering same
shall not apply the presumption that the terms hereof shall be more strictly
construed against a party by reason of the rule or conclusion that a document
should be construed more strictly against the party who itself or though its
agent prepared the same, it being agreed that all parties hereto have
participated in the preparation of this lease and that legal counsel was
consulted by each party hereto before the execution of this lease.

        Section 34.17.   Tenant shall not, without the prior written consent of
        --------------
Landlord, use the name of the Building for any purpose other than as the address
of the business to be conducted by Tenant in the Premises, nor shall Tenant use
the name of the Building as Tenant's business address after Tenant vacates the
Premises, nor shall Tenant do or permit the doing of anything in connection with
Tenant's business or advertising which in the reasonable judgment of Landlord
may reflect unfavorably on Landlord or the Building or confuse or mislead the
public as to any apparent connection or relationship between Landlord, the
Building, and the Tenant.

        Section 34.18.   Any elimination or shutting off of light, air, or view
        --------------
by any structure which may be erected on lands adjacent to the Building and not
located on the Land shall in no way affect this lease or impose any liability on
Landlord.

        Section 34.19.   The exhibits referred to in the Basic Lease Information
        --------------
are by this reference incorporated fully herein. The term "this lease" shall be
considered to include all such exhibits.

        Section 34.20.   As provided in Section 1.01, during the Term, Landlord
        --------------
shall allow Tenant and Tenant's officers, employees and invitees reasonable
access and use of the cafeteria in the INTELSAT Headquarters Building, subject
to any and all reasonable Rules and Regulations pertaining thereto that Landlord
may from time to time adopt.

        Section 34.21.   An electronic building security system of a similar
        --------------
nature and quality as the electronic building security system now operating in
the Phase I building on the Land shall be provided by Landlord at Landlord's
sole cost and expense to limit access to the Building. It is understood and
agreed that Landlord shall not be responsible for the quality of such system, or
for any damage or injury to Tenant, its employees, invitees or others due to any
failure of such system.

        Section 34.22.   Landlord warrants and represents to Tenant that the
        --------------
aggregate amount of floor space of the Premises plus the Expansion Space,
together with the amount of all other floor space in the INTELSAT Headquarters
Building currently leased to persons or entities other than Priority Subtenants
(as such term is defined in the Ground Lease) does not equal or exceed twenty
percent (20%) of the total floor space above grade of the INTELSAT Headquarters

                                     -49-
<PAGE>

Building.  Landlord understands that Tenant is relying on this representation in
not seeking approval of the "Planning Commission" as to this lease under the
terms of Article 7(l)(g) of the Ground Lease.

        Section 34.23.   Under the provisions of the Ground Lease, in the event
        --------------
of termination thereof, the "Lessor" will be obligated to make payment to the
"Lessee" of amounts equal to the rent theretofore paid by the "Lessee" (reduced
as therein provided) and amounts equal to the value as therein defined (reduced
as therein provided) of Improvements constructed pursuant to the Ground Lease
and certain other costs incurred by the "Lessee" (all such amounts being herein
collectively called "Ground Lessor Payments"), all as more fully set forth in
Article 8.5 of the Ground Lease. Landlord hereby grants a security interest, as
provided in the Uniform Commercial Code, in and to Landlord's rights under the
Ground Lease with respect to the Ground Lessor Payments and in and to all Ground
Lessor Payments which become payable to Landlord under and pursuant to the
Ground Lease, and the proceeds thereof, as security for the payment of all
amounts which may become due and owing from Landlord to Tenant pursuant to
Section 25.04 of this Lease. Landlord agrees that Tenant shall have all rights
of a secured party as provided in the Uniform Commercial Code with respect to
the security interest hereinabove granted and agrees, upon request by Tenant
from time to time, to execute and deliver to Tenant financing statements and
renewal financing statements as may be required to perfect and continue the
perfection of the security interest herein granted to Tenant under the
provisions of the Uniform Commercial Code. Tenant agrees, however, that if a
nondisturbance agreement from the "Lessor" under the Ground Lease as described
in Section 25.03 is obtained and furnished to Tenant, then the provisions of
this Section 34.23 shall cease and terminate and shall be of no further force or
effect and Tenant will, upon request, release the security interest in the
Ground Lessor Payments hereinabove granted to Tenant. Further, Tenant agrees
that (if such security interest is not released as provided for above) and if
Landlord is not then in default in the payment of any amount then due by
Landlord to Tenant under this Lease, Tenant will, upon request, subordinate its
security interest in the Ground Lessor Payments granted hereinabove to a
security interest in the Ground Lessor Payments granted to any lender not
related to Landlord which has been granted a first lien upon Landlord's interest
in the Ground Lease, Land and INTELSAT Headquarters Building to secure a loan (a
"Secured Loan") to Landlord; provided, that and if (a) the total principal
amount of the Secured Loan to which Tenant's security interest is to be
subordinated does not exceed eighty percent (80%) of the then current appraised
fair market value of the INTELSAT Headquarters Building [as determined by the
appraisal referred to in clause (b)] and (b) Landlord furnishes to Tenant a
signed copy of a current appraisal of the INTELSAT Headquarters Building by a
qualified, independent appraiser who shall be an MAI-certified real estate
appraiser with ten years experience in the District of Columbia office building
market reflecting that the appraised fair market value of the INTELSAT
Headquarters Building is then at least one hundred twenty-five percent (125%) of
the total principal amount of such Secured Loan. Tenant may not be required to
subordinate its security interest in the Ground Lessor Payments to security
interests securing more than one Secured Loan at any one time, but if the liens
and security interests securing a Secured Loan to which Tenant's security
interest has been subordinated are released, then Tenant will, subject to the
terms and conditions set out hereinabove, thereafter subordinate its security
interest in the Ground Lessor Payments to a security interest securing a new
Secured Loan. For purposes hereof, if a single lender has made one or more loans
secured by one or more deeds of trust of which at least one deed of trust, is It
a first lien upon Landlord's interest in the Ground Lease, Land and INTELSAT
Headquarters

                                     -50-
<PAGE>

Building, all of such deeds of trust securing such lender shall be treated as
constituting a first lien and all of such loans made by such lender shall be
treated as constituting one Secured Loan. In the event that the provisions of
this Section 34.23 have not been terminated pursuant to the provisions hereof,
Landlord may, in addition to and not in limitation of Landlord's rights to
obtain subordination of its security interest in the Ground Lessor Payments,
require Tenant to release its security interest in the Ground Lessor Payments
provided that Landlord deposits with an escrow agent designated by Landlord that
meets with Tenant's reasonable satisfaction, pursuant to an escrow agreement
prepared by Landlord that meets with Tenant's reasonable satisfaction, the sum
of One Million Five Hundred Dollars ($1,500,400) (or an irrevocable letter of
credit in the amount of $1,500,000) to be held by the escrow agent during the
remainder of the term of this Lease as security for the payment by Landlord of
any amounts that may be payable by Landlord to Tenant pursuant to Section 25.04
hereof, but to be returned to Landlord in the event and at such time that a
nondisturbance agreement from the "Lessor" under the Ground Lease as described
in Section 25.03 is obtained and furnished to Tenant. Interest on the escrow
deposit while held in escrow shall be paid to Landlord.

     EXECUTED under seal as of the date first written above.

LANDLORD                                TENANT

International                           WLJA Inc.
Telecommunications
Satellite Organization
                                        By:    /s/ Thomas B. Cookerly
                                              -------------------------------
                                        Name:    Thomas B. Cookerly

By:     /s/ Richard R. Colino           Title:  President & General Manager
    --------------------------------
    Richard R. Colino
    Director General                    Attest:

Attest:                                 By:    /s/ Joe L. Allbritton
                                              -------------------------------
   [sig]                                Name:  Joe L. Allbritton
------------------------------------

                                        Title:  Chairman of the Board

                                        [Corporate Seal]

                                     -51-
<PAGE>

                                  INTEL-L-611

                                   EXHIBIT A

                                  FLOOR PLANS

                                 Page No. A-1

                                     -52-
<PAGE>

                                  INTEL-L-611

                                   EXHIBIT A

                                  FLOOR PLANS

                                  Page No. A-2

                                     -53-
<PAGE>

                                  INTEL-L-611

                                   EXHIBIT A

                                  FLOOR PLANS

                                  Page No. A-3

                                     -54-
<PAGE>

                                  INTEL-L-611

                                   EXHIBIT A

                                  FLOOR PLANS

                                  Page No. A-4

                                     -55-
<PAGE>

                                  INTEL-L-611

                                   EXHIBIT A

                                  FLOOR PLANS

                                  Page No. A-5

                                     -56-
<PAGE>

                                  INTEL-L-611

                                   EXHIBIT A

                                  FLOOR PLANS

                                  Page No. A-6

                                     -57-
<PAGE>

                                  INTEL-L-611

                                   EXHIBIT A

                                  FLOOR PLANS

                                  Page No. A-7

                                     -58-
<PAGE>

                                  INTEL-L-611

                                   EXHIBIT A

                                  FLOOR PLANS

                                  Page No. A-8


                                     -59-
<PAGE>

                                   EXHIBIT B
                                   ---------

                                      LAND
                                      ----



     Being part of the easternmost lot (508,582.70 square feet) shown on a plat
entitled Plat of Computation on a Tract of Land "Taxed as Square 2055" recorded
         -------------------------------------------------------------
in the Office of the Surveyor of the District of Columbia in Survey Book 199 on
Page 81, said lot also being taxed as part of Lot 800 in Square 2055, and being
more particularly described as follows:

     Beginning at an iron pipe planted at the northeast corner of the lot on the
edge of Connecticut Avenue; thence with the boundary of the lot on the southwest
side of Connecticut Avenue

<TABLE>
<S>                                      <C>
1.  South 24 degrees 26'00"              East, 207.14 feet; thence three courses
                                         across the lot
2.  South 45 degrees 04'00"              West, 190.31 feet; thence
3.  South 0 degrees 04'00"               West, 297.50 feet; thence
4.  South 46 degrees 54'22"              East, 174.93 feet to the north side of
                                         Tilden Street, N.W.: thence two courses on
                                         the boundary of the lot on the north side of
                                         Tilden Street
5.  134.02 feet on the arc of a          curve to the left with a radius of 1271.60
                                         feet and a chord bearing South 74030'46"
                                         West, 133.96 feet to a point of reversed
                                         curvature; thence
6.  202.39 feet                          on the arc of a curve to the right with a
                                         radius of 1851.04 feet and a chord bearing
                                         South 74037'33" West, 202.29 feet; thence
                                         two courses across the lot
7.  North 0 degrees 04'00"               East, 54.03 feet; thence
8.  North 89 degrees 56'00"              West, 227.00 feet to the South 0 degrees 04" West,
                                         839.65 foot boundary of the lot; thence with
                                         said boundary reversed
9.  North 0 degrees 04"00"               East, 565.8 feet; thence ten courses across
                                         the lot
10.  South 89 degrees 56"00"             East, 17.00 feet to a point of curvature;
                                         thence
</TABLE>

                                     -60-
<PAGE>

<TABLE>
<S>                                      <C>
11.  25.50 feet                          on the arc of a curve to the left with a
                                         radius of 53.27 feet and a chord bearing
                                         North 76 degrees 21"06" East, 25.26 feet to a point
                                         of compound curvature; thence
12.  42.47 feet                          on the arc of a curve to the left with a
                                         radius of 253.45 feet and a chord bearing
                                         North 54 degrees 52'35" East, 42.34 feet to a point
                                         of compound curvature; thence
13.  32.37 feet                          on the arc of a curve to the left with a
                                         radius of 253.45 feet and a chord bearing
                                         North 43 degrees 27'25" East, 32.35 feet to a point
                                         of tangency, thence
14.  North 39 degrees 47'52"             East, 11.70 feet to a point of curvature;
                                         thence
15.  42.14 feet                          on the arc of a curve to the right with a
                                         radius of 101.85 feet and a chord bearing
                                         North 51 degrees 38'59" East, 41.84 feet to a point
                                         of compound curvature; thence
16.  35.47 feet                          on the arc of a curve to the right with a
                                         radius of 279.34 feet and a chord bearing
                                         North 67 degrees 08'21" East, 35.44 feet to a point
                                         of reversed curvature; thence
17.  27.96 feet                          on the arc of a curve to the left with a
                                         radius of 138.52 feet and a chord bearing
                                         North 64 degrees 59'40" East, 27.91 feet to a point
                                         of compound curvature; thence
18.  58.77 feet                          on the arc of a curve to the left with a
                                         radius of 78.97 feet and a chord bearing
                                         north 37 degrees 53'30" East, 57.42 feet to a point
                                         of compound curvature; thence
19.  50.65 feet                          on the arc of a curve to the left with a
                                         radius of 175.82 feet and a chord bearing
                                         North 8 degrees 19'08" East, 50.47 feet to the North
                                         89 degrees 56' West, 446.84 foot boundary of the
                                         lot; thence with said boundary reversed
20.  South 89 degrees 56'00"             East, 232.84 feet to the point of beginning,
</TABLE>

                                     -61-
<PAGE>

<TABLE>
<S>                                      <C>
                                         containing 7.7168 acres of land and as shown
                                         on a plot prepared by Kidde Consultants,
                                         Inc. dated June 6, 1982 and entitled "Plot
                                         Showing Proposed Division Of Intelstat
                                         Headquarters Building Site For Lease
                                         Purposes."
</TABLE>

                                     -62-
<PAGE>

                                   EXHIBIT C
                                   ---------

                             LEASEHOLD IMPROVEMENTS
                             ----------------------

                                   ARTICLE 1
              (Includes Base Building Work and Tenant Build-Out)

                                  DEFINITIONS

     The terms defined in Article 1 of this Exhibit C, for all purposes of this
Exhibit C, shall have the meanings herein specified, and, in addition to the
terms defined herein, the definitions in the Basic Lease Information and
otherwise in this lease shall also apply to this Exhibit C.

1.01  "Base Building Work" shall mean the improvements in and about the
----  Premises as set forth in Exhibit C-1.

1.02  "Building Plans and Specifications" shall mean plans and specifications
----  for the Building prepared by John Andrews International Pty. Ltd. or
      VVKR Inc. and as modified in accordance with Section 1 of Exhibit C-2.

1.03  "Tenant's Contractor" shall mean such reputable contractor selected by
----  Tenant for interior buildout (subject to Landlord's approval which shall
      not unreasonably be withheld) to construct and install the Tenant
      Build-out in the Premises.

1.04  "Tenant Build-out" means the items which are supplied, installed, and
----  finished in the Premises by or on behalf of Tenant, at Tenant's expense,
      as provided for hereinbelow.  The design of the Tenant Build-out shall
      be consistent with sound architectural and construction practices for
      similar first-class office buildings in the District of Columbia.

1.05  "Interior Construction Plans" shall mean full, complete, and accurate
----  architectural working drawings and specifications for the Tenant
      Build-out for the Premises prepared at Tenant's expense by Tenant's
      Architects including all architectural dimensioned plans showing wall
      layouts, door locations, power and telephone locations and reflected
      ceiling plans; and further including, elevations, details,
      specifications and schedules according to accepted AIA standards, which
      shall be consistent with the Building Plans and Specifications.

1.06  "MEP Plans" shall mean mechanical, electrical and plumbing plans,
----  schedules and specifications for the Tenant Build-out for the Premises.
      MEP Plans which do not impact the Base Building Systems will be prepared
      at Tenant's expense by Tenant's MEP Engineers in accordance and in
      compliance with the requirements of applicable building, plumbing, and
      electrical codes and the requirements of any authority having

                                     -63-
<PAGE>

      jurisdiction over or with respect to such plans, schedules and
      specifications, which are complete, accurate, consistent and fully
      coordinated with the Building Plans and specifications.  All other MEP
      Plans will be prepared by the Landlord's Architect after receipt of
      Tenant Preliminary Plans.  The Tenant shall have an opportunity to
      review the Landlord's Architect's plans, which shall be consistent with
      the intent of the Tenant Preliminary Plans.

1.07  "Structural Plans" shall mean structural plans, schedules and
----  specifications, if any, for the Tenant Build-out for the Premises,
      prepared by Landlord's Architect at Landlord's expense after receipt of
      Tenant Preliminary Plans and in accordance with the requirements of
      Exhibit C-2.  The Tenant shall have an opportunity to review the
      Landlord's Architect's plans, which shall be consistent with the intent
      of the Tenant Preliminary Plans.

1.08  "Tenant's Architect" shall mean Settles Associates Inc. or such other
----  reputable person or persons engaged by Tenant and approved by Landlord
      (such approval not to be unreasonably withheld) to prepare the Tenant
      Interior Construction Plans.

1.09  Tenant's MEP Engineers" shall mean Setty and Associates or such other
----  engineers engaged by Tenant and approved by Landlord (such approval not
      to be unreasonably withheld) to prepare the MEP Plans, complete with all
      calculations which impact existing equipment and structure, for the
      Tenant Build-out not affecting Base Building Systems.

1.10  "Tenant's Structural Engineers" shall mean Cagley and Associates or such
----  other structural engineers engaged by Tenant and approved by Landlord
      (such approval not to be unreasonably withheld) to prepare the Tenant
      Preliminary Plans for Tenant requested structural changes.

1.11  "Landlord's Architect" shall be VVKR Inc. in association with MMP and
----  The Benham Group or any other reputable architect or engineering firms
      engaged by the Landlord.

1.12  "Base Building Systems" shall be defined as any usable building systems
----  or components which are external to Tenant space within the core of the
      Building and/or common to and/or serve or exist for the benefit of other
      tenants or occupants of the Building.

1.13  "Tenant Preliminary Plans" shall mean structural and MEP information in
----  sufficient detail to enable the Landlord's Architect to prepare detailed
      Building Plans and Specifications.  The final version of the Tenant
      Preliminary Plans shall be marked "Final Preliminary Plans."

                                     -64-
<PAGE>

1.14  "Plans" shall mean the Interior Construction Plans together with the MEP
----  Plans, for which Tenant is responsible and if applicable, the Final
      Preliminary Plans.

1.15  "Landlord's Contractor" shall mean the W.P. Lipscomb Company or any
----  other reputable Contractor selected by the Landlord.

                                   ARTICLE 2
                              SUBMISSION OF PLANS

2.01  Upon Tenant's request, Landlord will furnish Tenant, one (1) set of
----  Building Plans and Specifications pertaining to Tenant's space to assist
      Tenant in preparing the Plans.  It is understood and agreed that
      Landlord in no way warrants the accuracy of such Building Plans and
      Specifications and Landlord shall not have any liability to Tenant, or
      anyone claiming through Tenant as a result of such plans.  Tenant, shall
      perform a field verification to independently determine the
      specifications and dimensions of the Premises.

2.02  Tenant, all Tenant's expense, has prepared and delivered to Landlord the
----  final version of the Tenant Preliminary Plans impacting the structure,
      and shall hereafter upon request promptly provide to Landlord any
      underlying detailed information Landlord may reasonably request in order
      to evaluate such plans.  On or before 15 January 1987, Tenant, at
      Tenant's expense, shall prepare and deliver to Landlord the final
      version of the remaining Tenant Preliminary Plans, preliminary space
      plans and Tenant's interior MEP Plans, and shall thereafter upon request
      promptly provide to Landlord any underlying detailed information
      Landlord may reasonably request in order to evaluate such plans.  The
      final version of the Interior Construction Plans shall be delivered to
      the Landlord by Tenant, at Tenant's expense, on or before 2 April 1987.
      No later than fifteen (15) business days after Landlord's receipt of
      each set of plans, Landlord shall notify Tenant in writing as to whether
      Landlord approves or disapproves such plans.  If Landlord requires any
      changes to such plans, Tenant shall, at Tenant's expense, prepare and
      deliver to Landlord the required revisions within ten (10) business days
      after Landlord's request for such revisions.  If the Landlord approves
      such plans, the Tenant and Landlord shall be authorized to Proceed with
      their respective responsibilities in accordance with such plan's and
      this Exhibit C.  Final plans referred to herein shall be in marked
      "Final Plans."

2.03  Upon completion of Tenant's Work the Tenant shall, upon receipt, furnish
----  Landlord with accurate "as built" plans of the Tenant's Work, which
      plans shall be incorporated into this Exhibit C by this reference for
      all intents and purposes.  Construction "as built" applicable to the
      Premises and maintained by the Landlord shall be available for perusal
      and copy by the Tenant.

                                     -65-
<PAGE>

2.04  All design, construction, and installation of Tenant Build-out shall
----  conform to the requirements of applicable building, plumbing and
      electrical codes and the requirements of any authority having jurisdiction
      over, or with respect to, such work.

                                   ARTICLE 3

                                LANDLORD'S WORK

Landlord shall, at its sole cost and expense, furnish, install and complete the
Base Building Work as defined in Exhibit C-1 and the Landlord's work as
described in Paragraphs 1A-1H of Exhibit C-2 ("Landlord's Work").

                                   ARTICLE 4

                                 TENANT'S WORK

4.01  All Tenant Build-out other than Landlord's Work ("Tenant's Work") shall
----  be at Tenant's sole cost and expense (but subject to payment of Landlord's
      Contribution pursuant to Articles 5.01 through 5.03 of Exhibit C) it being
      understood and agreed that any Tenant Work which affects the structure of
      the Building of the Base Building Systems shall be performed by Landlord,
      at Tenant's expense. The Tenant may elect to contract directly with
      outside Contractors for the interior Tenant Build-out Work.

4.02  The Tenant's Work shall comply with the requirements set forth in
----  Exhibit C-2.

                                   ARTICLE 5

                         TENANT IMPROVEMENT ALLOWANCE

5.01  In addition to Landlord's contribution described in Article 3 of this
----  Exhibit C, Landlord shall pay in accordance with this Article 5 on behalf
      of Tenant an amount up to [redacted text] multiplied Rentable Area of the
      Premises toward the construction of Tenant's Work and related consulting
      fees (hereinafter "Landlord's Contribution"). Landlord's Contribution
      shall be paid on behalf of Tenant as set forth below.

5.02  Landlord shall pay the Landlord's Contribution to Tenant periodically as
----  written requests for payment (the "Payment Requests") are submitted to
      Landlord by Tenant based upon copies of invoices from Tenant's Contractor,
      consultants and/or other contractors constructing or supplying Tenant's
      Work and material, which Payment Requests shall include a detailed
      description of the portion of the Tenant's Work performed during

                                     -66-
<PAGE>

      the period to which any such Payment Request relates and proof of payment
      of previous invoices submitted to and paid by Landlord. Landlord shall pay
      the amount so requested by Tenant to Tenant within fifteen (15) days after
      a Payment Request is submitted to Landlord.

5.03  For purposes of this Exhibit C, the Rentable Area of the Premises is
----  estimated to be 73,153 square feet.  The amount of any payments payable
      to Tenant pursuant to this Article 5 shall be adjusted upon the
      determination of the Rentable Area of the Premises pursuant to Section
      1.02 or Section 6.04 of the lease (it being agreed that if Tenant
      exercises its option to lease the Expansion Space under Article 33 of
      the lease the Rentable Area of the Expansion Space shall be included in
      the Rentable Area of the Premises for purposes of this Article 5.03).
      If the payments made to or on behalf of Tenant on the basis of the
      estimated Rentable Area of the Premises exceed [redacted text]
      multiplied by the actual number of square feet of the Rentable Area of
      the Premises, Tenant shall pay Landlord such excess promptly after such
      determination.  If the payments made to or on behalf of Tenant on the
      basis of the estimated Rentable Area of the Premises are less than
      $25.00 multiplied by the actual square feet of Rentable Area of the
      Premises, Landlord shall pay Tenant such shortfall promptly after such
      determination.

5.04  Tenant shall have the right, at its option, to use, in its interior
----  design, the equipment and materials purchased by INTELSAT in bulk for
      the build out of the interior of Phase II.  The equipment and materials
      available are as follows:

<TABLE>
<CAPTION>
                                     Quantity            Unit
      Description                    Available           Price
     ------------------------------  ------------------  ------------
<C>  <S>                             <C>                 <C>
1.   Metal door frames
     Type 1-1  Left Hand             300 Sets
     with Glass
     Sidelight
     Type 1A-1  Right Hand           200 Sets
     with Glass
     Sidelight
     Type 2-2  Left Hand             50 Sets
     Single Door
     Frame
     Type 2A-1  Right Hand           58 Sets
     Single Door
     Frame
</TABLE>

                                     -67-
<PAGE>

<TABLE>
<C>  <S>                             <C>                 <C>
2.   Light Fixtures
     Type A  Gibson                  (Adequate Supply)
     Paralux Series
     18 Cell, (2'X4')
     Recessed/Air
     Supply 277 Volts
3.   Sconce Lights - Cylinder        144 Fixtures
     Type Wall Lamp 14" Tall
4.   Patrick Carpet                  (Adequate Supply)   per sq. yd.
     Title (18"X18")
</TABLE>

      The above equipment or materials are available for purchase by the
      Tenant from the Landlord at the above stated acquisition unit prices
      paid by the Landlord.

5.05  The Landlord will make every reasonable effort to enable the Tenant Work
----  to commence as soon as possible.  The parties understand that Base
      Building Work and Tenant's Work will be conducted concurrently and
      accordingly in order to ensure harmony between subcontractors of like
      trades the Tenant shall consider using the Landlord's Contractor and his
      subcontractors for the Tenant's Work whenever possible.  In the event
      other contractors/subcontractors are selected by the Tenant, the other
      contractors/subcontractors shall conduct their work without interruption
      of or disruption to the Landlord's Contractor and its subcontractors'
      work.

5.06  The Landlord's procurement staff is available to provide its best
----  efforts for use by the Tenant to obtain bids, negotiate contract prices,
      award and administer such contracts on behalf of the Tenant.  This
      service is available to the Tenant at no additional charge or fees over
      and above the actual cost of the contracts awarded on behalf of the
      Tenant.  Decision as to bidders, contract awards and amendments or
      changes to contracts will be subject to the participation and approval
      of the Tenant.  Any and all costs for the services provided in
      accordance with the procurement services set forth herein shall be paid
      by the Tenant to the Landlord within fifteen (15) days after a request
      therefor is submitted to the Tenant.

5.07  At all times prior to the Commencement Date Landlord shall, at its
----  expense, provide electricity and to the extent that heating, ventilating
      and air-conditioning facilities are installed in the Building, heating,
      ventilating and air-conditioning to the Building and Premises as
      reasonably required by Tenant and its contractors incident to
      performance and completion of Tenant's Work.

                                     -68-
<PAGE>

                                   ARTICLE 6

                           TENANT REQUESTED CHANGES

     Tenant shall not deviate from the Plans approved in accordance with Article
2.02 of this Exhibit C without Landlord's prior written approval, which approval
shall be granted by Landlord if and to the extent that Landlord's approval is
required under Section 12.01.  All change requests shall be submitted to
Landlord together with preliminary drawings and other information as may be
reasonably necessary to enable Landlord to either approve or disapprove such
changes.  Landlord shall thereafter either approve or not approve the
preliminary drawings within fifteen (15) days.  In the event Landlord approves
such changes, and provided such changes do not affect the structure of the
Building or the Base Building Systems, Tenant may perform the work, and upon
completion furnish Landlord with "as built" drawings.  If the change order
request involves changes to either the structure of the Building or the Base
Building Systems, and if Landlord approves the changes based on the preliminary
drawings, Landlord shall prepare detailed plans and specifications for such
work, at Tenant's sole cost and expense, and Landlord shall thereafter perform
such work at Tenant's sole cost and expense.  If any change requested by Tenant
which deviates from the approved Plans delays the date of substantial completion
of the Base Building Work, such delay shall be the sole responsibility of Tenant
and be considered a "Tenant Delay." Implementation of Interior Construction
Plans shall be the responsibility and at the sole expense of the Tenant.

                                     -69-
<PAGE>

                                   ARTICLE 7

                            COMMENCEMENT OF RENTAL

     In the event and to the extent Landlord is delayed in substantially
completing the Base Building Work or the Landlord's Work as a result of

     1.   Tenant's failure to deliver to Landlord the Plans on or before the
          dates specified in Article 2.02 of this Exhibit C, or

     2.   Tenant requested changes as described in Article 6 after approval of
          Plans in accordance with Article 2.02 of this Exhibit C, then

     the Tenant's obligation to pay Rental shall be accelerated by the number of
days of such Tenant delay.

                                     -70-
<PAGE>

                                  EXHIBIT C-1
                                  -----------

                              BASE BUILDING WORK
                              ------------------

     The Landlord shall at its sole cost and expense provide a Building Shell
consisting of the following (the "Base Building Work"):

     (1)  Class exterior walls and core walls taped, spackled and ready for
          finish or building standard paint, in such manner as befits a first-
          class office building in the District of Columbia.

     (2)  Unfinished, level and smooth concrete floors installed throughout the
          Premises, broom clean, with office floors designed for a per square
          foot load of 80 pounds live and 20 pounds dead.

     (3)  120/208 volt and 277/480 volt power supplied on each Floor to the
          Building core and terminated in branch circuit panel boards.

     (4)  Men's and ladies' restroom facilities furnished in accordance with the
          Building Plans and Specifications and located on each floor on which
          the Premises are located.

     (5)  Heating, Ventilating, and Air Conditioning

          (A)  High pressure supply air duct work from high pressure variable
               air volume air handling located in mechanical rooms, to the
               perimeter of the Premises.

          (B)  Interior areas are conditioned by low pressure supply air duct
               work from low pressure constant volume variable temperature air
               handling units located in mechanical rooms located outside the
               Premises.

     (6)  Voice evacuation system, smoke detectors, exit lights, fire
          sprinklers, fire standpipe valves and pull stations to meet the
          District of Columbia Fire Code.

     (7)  All exterior walls completed with thermal insulation and double
          glazing.

     (8)  All floor openings, and stair openings located in the core installed
          with fire rated drywall enclosures and standard fire rated doors.

     (9)  Water, waste and vent Plumbing risers outside of the core area on each
          of the floors.

     (10) Lobby level closure doors, one double door per pod.

     (11) Landlord will bring HVAC ducts and piping to the perimeter of the
          Premises, in accordance with HVAC system provided by the Landlord
          which will accommodate the present needs of the Tenant's television
          station (WLJA), which

                                     -71-
<PAGE>

          in turn will be described in the final MEP Plans to be submitted on or
          before 15 January 1987 and shall be reasonably consistent with the
          Setty Report 4 August 1986 entitled "Preliminary Analysis of
          Mechanical/Electrical Systems for WJLA-TV."

     (12) All design, construction and installation of Base Building Work and
          Landlord's Work shall conform to the requirements of applicable
          building, plumbing and electrical codes and the requirements of any
          authority having jurisdiction over, or with respect to, such work.

                                     -72-
<PAGE>

                                  EXHIBIT C-2
                                  -----------

                            3400 INTERNTIONAL DRIVE
                            -----------------------

                    REQUIREMENTS FOR LEASEHOLD IMPROVEMENTS
                    ---------------------------------------

     1.  The Landlord's Work referred to in Article 3 shall consist of the
following:

          A.   Depressed slab for computer and equipment rooms in Pod P.  Level
               1 (to maximum of 12") and Level 2 and 4 (to maximum of 8") .

          B.   Elimination of the floors in the area on levels 3 and 5 of Pod P
               in accordance with the preliminary plans submitted or to the
               submitted pursuant to the first sentence of Article 2.02 of this
               Exhibit C.

          C.   Provide personnel access between Phase I and II for use of the
               main INTELSAT cafeteria by Tenant's employees and personnel.

          D.   Re-cut and weld steel beams to increase vertical room area in
               Level 2 Pod N for raised ceiling.

          E.   Provide the framing for opening in floor for newsroom stairway in
               Pod N between Level 1 and 2.

          F.   Provide the framing for opening for the link stairway in Pod P
               level 2 through 5, and if the option for added floor is
               exercised, through Level 6.  In the event the NCPC approval for
               the link stairway is not obtained by the Tenant before 31 January
               1987, the Atrium stairway will be provided in lieu thereof at the
               sole cost and expense of the Tenant, except the Landlord will be
               responsible for design, security and fire safety aspects of the
               Atrium stairway and will pay to the Tenant a fixed amount of
               Twenty-Five Thousand Dollars ($25,000) provided the NCPC approval
               of the link stairway is not obtained and the Atrium stairway is
               constructed in lieu thereof.

          G.   Provide the framing for opening for the elevator from Pod P
               Level 1 through Level 4.

          H.   Provide separate metering for Tenant power usage to the maximum
               practical extent.

     2.  Any and all other improvements shall be at the sole cost and expense of
the Tenant.  Such improvements which affect or require Building structural
changes or which impact the Base Building Systems are subject to the following:

          A.   Such Tenant requested improvements to Pod N shall be kept to the
               minimum and only made if the present proposed Building structure
               and

                                     -73-
<PAGE>

               MEP Systems, as set forth in the Building Plans and
               Specifications, cannot possibly be used.

          B.   Such Tenant requested improvements shall be submitted to the
               Landlord in writing, complete with adequate preliminary drawings,
               (at the earliest practicable date) in order to minimize the
               effect on the Building construction schedule.  Such Tenant
               requested improvements will be submitted by the Landlord to
               Landlord's Architect for preparation of the necessary
               construction drawings and then the Landlord will issue change
               instructions to the Landlord's Contractor to accomplish the
               required work.

          C.   The charges for such other Tenant requested improvements will be
               borne solely by the Tenant.  These charges will include all
               direct costs to the Landlord including the following:

               1.   Costs of the efforts of the Landlord's Architect and its
                    consultants.

               2.   Costs of reproduction of necessary drawings.

               3.   Costs of labor, materials, overhead, and fees of the
                    Landlord's Contractor and its subcontractors, including
                    costs of necessary rescheduling of work.

               4.   Charles of the Landlord's Consultants for inspection and
                    acceptance of such Tenant requested improvements.

               5.   There will be no overhead or fee added by Landlord to the
                    costs referred to above for the Landlord's work in
                    connection therewith.

          D.   Such costs for Tenants requested leasehold improvements will be
               paid by the Tenant to the Landlord within fifteen (15) days after
               requests for payment for costs theretofore incurred by Landlord
               are submitted to the Tenant.

                                     -74-
<PAGE>

                                   EXHIBIT D
                                   ---------

                     DECLARATION AS TO DATE OF DELIVERY AND

                      ACCEPTANCE OF POSSESSION OF PREMISES
                      ------------------------------------

     Attached to and made a part of the lease dated the ____ day of
_______________, 19__, entered into by and between International
Telecommunications Satellite Organization, as Landlord, and
________________________________________________, as Tenant.

     Landlord and Tenant do hereby declare and evidence that possession of the
Premises was accepted by Tenant on the _______ day of _______________________,
19__, and the lease is now in full force and effect.  For the purpose of this
lease, the Commencement Date is established and declared as the ____________ day
of __________, 19__.

                                      LANDLORD:

ATTEST:                               International Telecommunications Satellite
                                      Organization


                                      By:
--------------------------------          -------------------------------------
                                      TENANT:

ATTEST:                               WJLA Inc.


By:                                   By:
   -----------------------------          -------------------------------------

Name:                                 Name:
     ---------------------------           ------------------------------------

Title:                                Title:
      --------------------------            -----------------------------------

[Corporate Seal]

                                     -75-
<PAGE>

                                   EXHIBIT E
                                   ---------

                      METHOD OF CALCULATING RENTABLE AREA

                            OF PREMISES AND BUILDING
                            ------------------------

     The Rentable Area of the Premises shall be calculated in accordance with
the Washington Board of Realtors Standard Method of Measurement except that the
Rentable Area of the Premises which would otherwise be determined in accordance
with the Washington Board of Realtors Standard Method of Measurement, a copy of
which is attached hereto, shall include two-thirds (2/3rds) of the floor space
to be removed on the third (3rd) and fifth (5th) levels of Pod P.  The Rentable
Area of the Building shall be calculated in accordance with the Washington Board
of Realtors Standard Method of Measurement except that two-thirds (2/3rds) of
the floor space to be removed on the third (3rd) and fifth (5th) levels of Pod P
shall also be included in the Rentable Area of the Building.  The Rentable Area
of the INTELSAT Headquarters Building shall be calculated in accordance with the
Washington Board of Realtors Standard Method of Measurement except that two
thirds (2/3) of the floor space to be removed on the third (3rd) and fifth (5th)
levels of Pod P shall also be included in the Rentable Area of the INTELSAT
Headquarters Building.

     In determining the Rentable Area of the Building and the Rentable Area of
the INTELSAT Headquarters Building, the Rentable Area of each floor of the
Building and the Rentable Area of each floor of the INTELSAT Headquarters
Building shall be calculated for purposes hereof as if each such floor were a
single tenancy floor.

                                     -76-