<PAGE>

                                                                 EXHIBIT 10.39.1

                    AMENDMENT TO LOAN AND SECURITY AGREEMENT

         Startec Global Communications Corporation, a Delaware corporation (the
"Borrower"), and NTFC Capital Corporation, a Delaware corporation (the "Lender")
enter into this Amendment to Loan and Security Agreement (this "Amendment") as
of the 30th day of June, 2000.

                              W I T N E S S E T H :
                              --------------------

         Whereas, Startec Global Communications Corporation, a Maryland
corporation ("Startec Maryland"), and Lender entered into that certain Loan and
Security Agreement dated as of December 31, 1998 (the "Loan Agreement"); and

         Whereas, Startec Maryland merged with Borrower, with Borrower as the
surviving corporation; and

         Whereas, Borrower transferred all, or substantially all, of its assets
to Startec Global Operating Company, a Delaware corporation ("Guarantor"); and

         Whereas, as a condition to Lender's consent to the merger of Startec
Maryland into Borrower and the transfer of all, or substantially all, of Startec
Maryland's assets to Guarantor, (a) Borrower subsequently assumed and agreed to
perform all the obligations of Startec Maryland as set forth in the Loan
Agreement pursuant to that certain Assumption Agreement dated March 26, 1999 by
Borrower for the benefit of the Lender and (b) Guarantor guaranteed the
obligations of Borrower under the Loan Agreement pursuant to that certain
Guaranty dated March 26, 1999 by Guarantor in favor of Lender; and

         Whereas, the Borrower and the Lender wish to amend the Loan Agreement
to increase the amount of credit available under the Loan Agreement and to make
certain additional modifications to the Loan Agreement.

         Now, therefore, in consideration of the foregoing, the mutual covenants
and agreements contained in this Amendment, and other good and valuable
consideration, the receipt and sufficiency of which each party hereby
acknowledges, the parties agree as follows:

                     ARTICLE 1: AMENDMENTS TO LOAN AGREEMENT

         1.01. COMMITMENT. The parties hereby amend Schedule 2.01 to the Loan
Agreement to increase the maximum principal amount of the Loan to $50,000,000
and to extend the date for drawing down until on or before December 31, 2000. In
addition, The parties hereby amend Section 2.01 of the Loan Agreement to read,
in its entirety, as follows:

                  2.01. COMMITMENT. Subject to the terms and conditions provided
         in this Agreement and as long as no Default has occurred and is
         continuing under this Agreement, the Lender shall lend to the Borrower
         from time to time before the Financing Termination Date, an aggregate
         principal amount not to exceed the amount set forth on SCHEDULE 2.01 to
         this Agreement as the maximum amount (the


<PAGE>

         "COMMITMENT"). The Lender and the Borrower acknowledge and agree that
         the outstanding principal balance of the Loan as of June 30, 2000 (the
         "Tranche 1 Amount),is $27,933,435. The remaining aggregate principal
         amount available under the Commitment, therefore, shall equal a maximum
         of $22,000,000 (the "Tranche 2 Amount"). The Borrower may use all of
         the available funds under the Tranche 2 Amount for general corporate
         purposes, including working capital (the "General Corporate Advances"),
         as well as for the purchase of Nortel Equipment and/or Vendor
         Equipment.

         1.02. EXISTING LOAN BALANCE. The Lender and the Borrower acknowledge
and agree that the outstanding principal balance of the Loan as of June 30, 2000
is $27,933,435.

         1.03 FINANCING TERMINATION DATE. The parties hereby amend Schedule 2.02
to the Loan Agreement to extend the Financing Termination Date to December 31,
2000.

         1.04. INTEREST RATE. The parties hereby amend the definition of
"Interest Rate" as set forth on Schedule 2.02 to the Loan Agreement to read, in
its entirety, as follows:

                  "INTEREST RATE": For each Advance comprising all or part of
         the Tranche 1 Amount, a fixed rate equal to the average yield to
         maturity on matching term Treasury Notes as reported in the Federal
         Reserve Statistical Release H.15(519) (the "Release") in effect three
         Business Days prior to the applicable Borrowing Date(s) plus the Rate
         Adjustment (as described in the Note). For each Advance comprising all
         or part of the Tranche 2 Amount, a fixed rate equal to the average
         yield to maturity on five-year Treasury Notes as reported in the
         Release in effect three Business Days prior to the applicable Borrowing
         Date(s) plus 4.50 percentage points. Interest shall accrue monthly
         based on a 365-day year.

         1.05. MATURITY DATE. The parties hereby amend the definition of
"Maturity Date" as set forth on Schedule 2.02 to the Loan Agreement to read, in
its entirety, as follows:

                  "MATURITY DATE": For each Advance comprising all or part of
         the Tranche 1 Amount, the 60th Payment Date (January 2, 2004) upon
         which date all then outstanding principal, interest, premium, expenses,
         fees, penalties and other amounts relating to the Tranche 1 Amount
         shall become due and payable. For each Advance comprising all or part
         of the Tranche 2 Amount, the 60th Payment Date after the date of the
         initial Advance comprising all or part of the Trance 2 Amount, upon
         which date all then outstanding principal, interest, premium, expenses,
         fees, penalties and other amounts relating to the Tranche 2 Amount
         shall become due and payable.

         1.06. MANDATORY PREPAYMENTS. In addition to the Mandatory Prepayments
currently required by the Loan Agreement, all General Corporate Advances in
excess of 40% of the aggregate Advances shall become immediately due and payable
from the proceeds of the sale of any equity securities, excluding the sale of
any equity securities relating to exercise of any existing stock options or
warrants, and/or Subordinated Indebtedness of the Borrower, if the net proceeds
to the Borrower from the sale exceed $50 million.

                                       2

<PAGE>

         1.07. ADDITIONAL COLLATERAL. As additional Collateral for the Loan, the
Borrower shall have its subsidiary, Startec Global Operating Company (the
"Operating Company"), grant a security interest to the Lender in all of the
assets of the Operating Company as additional Collateral securing the Operating
Company's obligations under that certain Guaranty Agreement, dated as of March
26, 1999. In addition, the Borrower shall grant a security interest to the
Lender in all of the capital stock of the Operating Company now held or later
acquired by the Borrower as additional Collateral securing the Obligation of the
Borrower under the Loan Agreement.

         1.08. ADDITIONAL GUARANTEES AND COLLATERAL. The Borrower represents and
warrants that the accounts receivable of the Operating Company currently exceed
85% of the consolidated accounts receivable of the Borrower. In addition to the
provisions of Section 3.09 of the Loan Agreement, the Borrower shall provide
additional guarantees and pledges of assets by its other Subsidiaries sufficient
to result in the Lender having a security interest in at least 85% of the
Borrower's consolidated accounts receivable as of the end of each fiscal quarter
of the Borrower.

         1.09. REGULATORY AUTHORIZATIONS. The parties hereby amend and replace
Schedule 4.05 to the Loan Agreement with the schedule attached as Exhibit A to
this Amendment.

         1.10. RESTRICTIONS ON LOANS. The parties hereby amend and replace
Schedule 4.07 to the Loan Agreement with the schedule attached as Exhibit B to
this Amendment.

         1.11. FINANCIAL STATEMENTS. The parties hereby amend and replace
Schedule 4.08 to the Loan Agreement with the schedule attached as Exhibit C to
this Amendment.

         1.12. ASSUMED NAMES. The parties hereby amend and replace Schedule 4.27
to the Loan Agreement with the schedule attached as Exhibit D to this Amendment.

         1.13 SUBSIDIARIES OF BORROWERS. The Borrower hereby amends and replaces
Schedule 4.30 to the Loan Agreement with the schedule attached hereto as Exhibit
E to this Amendment.

         1.14. FINANCIAL COVENANTS. The parties hereby amend and replace
Schedule 7.14 to the Loan Agreement with the form of schedule attached as
Exhibit F to this Amendment.

         1.15. EQUIPMENT LOCATED IN FRANCE. With regard to any additional
Equipment financed or refinanced by the Loan which the Borrower intends to
locate in France, the Borrower or its applicable Subsidiary shall pledge the
Equipment in accordance with the regulations of the law no. 51-59 dated 18
January 1951; provided, further, that the Borrower or its applicable Subsidiary
shall serve as the direct purchaser and the real user of the Equipment, the
Borrower or its applicable Subsidiary shall execute the appropriate pledge
documentation within two months after the first delivery of any of the Equipment
in France, and the Borrower or its applicable Subsidiary shall register the
pledge with the relevant Tribunal de Commerce within 15 days after the execution
of the pledge documents.

                             ARTICLE 2: AFFIRMATIONS

         The Borrower hereby represents and warrants that (a) on the date of
this Amendment no Default or Event of Default has occurred and is continuing or
exists or will occur or exist after giving effect to this Amendment; (b) the
execution and terms of this Amendment have been duly authorized by all necessary
and appropriate corporate action; and (c) the representations and warranties
contained



                                       3
<PAGE>

in Article 4 of the Loan Agreement, as amended by this Amendment, remain true
and correct on and as of the date of this Amendment as though made on and as of
the date of this Amendment, except as follows:

         2.01. The first sentence of Section 4.01 should read, "The Borrower is
duly organized, validly existing, and in good standing as a corporation under
the laws of Delaware.

         2.02. The word "Borrower" in Sections 4.05, 4.13 and 4.36 should change
to read "the Borrower or one or more Subsidiaries of the Borrower."

         2.03. The representation made in Section 4.14 remains true as of the
date of the Certificate of Financial Condition referred to in Section 4.14.

         2.04. The Borrower's federal taxpayer identification number set forth
on Schedule 1 should change to 52-2099559.

                              ARTICLE 3: CONDITIONS

         3.01. The effectiveness of this Amendment shall depend on the
fulfillment of all of the following conditions precedent:

                  (a) The Lender shall have received a Certificate of Financial
         Condition of the Borrower executed by one of its officers dated as the
         date of this Amendment.

                  (b) The Lender shall have received a fully-executed Amended
         and Restated Promissory Note in the amount of $50,000,000 substantially
         in the form of Exhibit G to this Amendment. The Lender promptly shall
         return the original executed Promissory Note to the Borrower with a
         signed notation marked on it as being amended and replaced by the
         Amended and Restated Promissory Note.

                  (c) The Lender shall have received a fully-executed
         Supplemental Security Agreement from the Operating Company in the form
         of Exhibit H to this Amendment.

                  (d) The Lender shall have received a fully-executed Pledge
         Agreement from the Borrower in the form of Exhibit I to this Amendment.

                  (e) The Lender shall have received a Consent and Agreement to
         Amendment by all of the Borrower's Subsidiaries that have guaranteed
         the Loan in the form of Exhibit J to this Amendment.

                  (f) The Lender shall have received an officer's certificate
         evidencing all actions taken by the Borrower and the Operating Company
         to authorize the execution, delivery and performance of the Borrower of
         this Amendment, the Amended and Restated Promissory Note, and the
         Supplemental Security Agreement, and the Pledge Agreement.



                                       4
<PAGE>

                  (g) The Lender shall have received a written opinion of
         counsel relating to the Borrower and the Operating Company
         substantially in the form of Exhibit K to this Amendment.

                            ARTICLE 4: MISCELLANEOUS

         4.01. Except as amended as provided above, the Loan Agreement shall
remain in full force and effect. The Borrower and the Lender hereby ratify the
Loan Agreement, as amended by this Amendment.

         4.02. Except to the extent otherwise provided in the Loan Agreement,
the laws of New York shall govern this Amendment and its construction.

         4.03. Unless otherwise specifically defined in this Amendment, all
capitalized terms used in this Amendment shall have the meanings assigned to
them in the Loan Agreement.

         IN WITNESS WHEREOF, the parties have duly executed this Amendment as of
the day and year first set forth above.

                                     Startec Global Communications Corporation

                                     By: /s/ PRABHAV V. MANIYAR
                                         ---------------------------------
                                         CFO

                                     NTFC Capital Corporation

                                     By: /s/ LI-BIN WANG
                                         ---------------------------------




                                       5
<PAGE>


                                                                SCHEDULE 7.14 TO
                                                     LOAN AND SECURITY AGREEMENT

                               FINANCIAL COVENANTS

         (a) TOTAL SECURED DEBT TO TOTAL CAPITALIZATION. At the time of each
Advance and at the end of each fiscal quarter, the Borrower shall maintain a
ratio of Total Secured Debt to Total Capitalization of not more than .50 to
1.00. For the purposes of that ratio, the following definitions shall apply:

                  (i) "TOTAL CAPITALIZATION": All equity as shown on the balance
         sheet of the Borrower plus all funded Indebtedness of the Borrower.

                  (ii) "TOTAL SECURED DEBT": Indebtedness of the Borrower
         secured by a Lien on the assets of the Borrower, excluding Indebtedness
         secured by accounts receivable.

         (b) CASH FLOW COVERAGE RATIO. The Borrower shall maintain a minimum
Cash Flow Coverage Ratio (measured at the end of each fiscal quarter for the
past four fiscal quarters) of at least 1.25, beginning at the end of the second
fiscal quarter of fiscal year 2002. For the purposes of that ratio, the
following definitions shall apply:

                  (i) "CASH FLOW COVERAGE RATIO": At the end of any fiscal
         period, the ratio of the Borrower's Cash Flow (as defined in the
         Agreement) plus interest income for the fiscal period to the Borrower's
         Debt Service for the fiscal period.

                  (ii) "DEBT SERVICE": For any fiscal period of Borrower, the
         sum of all principal and interest payments that Borrower is required to
         make during the period on account of all of its Indebtedness, including
         (without limitation) (a) amounts due during the period on account of
         capitalized leases; (b) the then current portion of any long-term
         Indebtedness, including any Subordinated Indebtedness; (c) amounts due
         on short-term Indebtedness; and (d) amounts due under this Agreement
         and the Note.

         (c) MINIMUM REVENUES. The Borrower shall maintain "Minimum Revenues" in
an amount equal to or greater than the quarterly amounts set forth below.

<TABLE>
<CAPTION>
                  QUARTER ENDED                               AMOUNT
                  -------------                               ------
<S>                                                   <C>
                  March 31, 2000                         $   59,534,000
                  June 30, 2000                              71,441,000
                  September 30, 2000                         77,394,000
                  December 31, 2000                          89,301,000
                  March 31, 2001                             71,739,000
                  June 30, 2001                              86,087,000
                  September 30, 2001                         93,261,000
                  December 31, 2001                         107,609,000
                  March 31, 2002                             90,133,999
                  June 30, 2002                             108,159,000
                  September 30, 2002                        117,173,000
                  December 31, 2002                         135,199,000

</TABLE>

<PAGE>

<TABLE>
<CAPTION>
                  QUARTER ENDED                               AMOUNT
                  -------------                               ------
<S>                                                   <C>
                  March 31, 2003                            102,751,000
                  June 30, 2003                             123,302,000
                  September 30, 2003                        133,577,000
                  December 31, 2003                         154,127,000
                  March 31, 2004                            117,137,000
                  June 30, 2004                             140,564,000
                  September 30, 2004                        152,278,000
                  December 31, 2004                         175,705,000

</TABLE>

         The phrase "Minimum Revenues" shall mean the Borrower's total
consolidated revenues for the fiscal quarter ending on the date of measurement.

         (d) MINIMUM EBITDA. The Borrower shall maintain "Minimum EBITDA" in an
amount equal to or greater than the quarterly amounts set forth below.

<TABLE>
<CAPTION>
                  QUARTER ENDED                               AMOUNT
                  -------------                               ------
<S>                                                    <C>
                  March 31, 2000                          $  (5,798,000)
                  June 30, 2000                              (6,394,000)
                  September 30, 2000                          2,000,000
                  December 31, 2000                           3,592,000
                  March 31, 2001                              3,675,000
                  June 30, 2001                               6,045,000
                  September 30, 2001                          8,441,000
                  December 31, 2001                          10,753,000
                  March 31, 2002                             11,046,000
                  June 30, 2002                              13,255,000
                  September 30, 2002                         13,807,000
                  December 31, 2002                          17,121,000
                  March 31, 2003                             15,275,000
                  June 30, 2003                              16,673,000
                  September 30, 2003                         17,438,000
                  December 31, 2003                          19,050,000
                  March 31, 2004                             18,635,000
                  June 30, 2004                              20,340,000
                  September 30, 2004                         21,274,000
                  December 31, 2004                          23,240,000
</TABLE>

         The term "Minimum EBITDA" shall mean the Borrower's EBITDA for the
fiscal quarter ending on the date of measurement. The term "EBITDA" shall mean,
for any fiscal period, the Borrower's actual operating earnings from ongoing
operations and before interest, taxes, depreciation and amortization for the
fiscal period.