FIRST POTOMAC REALTY INVESTMENT LIMITED PARTNERSHIP 7600 Wisconsin Avenue, 11th Floor Bethesda, Maryland 20814

FIRST POTOMAC REALTY INVESTMENT LIMITED PARTNERSHIP
7600 Wisconsin Avenue, 11^th Floor
Bethesda, Maryland 20814

Dated as of: November 30, 2007

KeyBank National Association,
as Administrative Agent
127 Public Square
Cleveland, OH 44114
Attention: John C. Scott

Ladies and Gentlemen:

We refer to the Secured Term Loan Agreement dated as of August 7, 2007 (as amended and in effect from time to time, the “Credit Agreement”), by and among FIRST POTOMAC REALTY INVESTMENT LIMITED PARTNERSHIP, a Delaware limited partnership (the “Borrower”), KEYBANK NATIONAL ASSOCIATION and the other lending institutions which are parties thereto (individually, a “Lender” and collectively, the “Lenders”), and KEYBANK NATIONAL ASSOCIATION, as administrative agent for itself and each other Lender (the “Agent”). Capitalized terms used in this letter of agreement (this “Amendment”) which are not defined herein, but which are defined in the Credit Agreement, shall have the same meanings herein as therein, as the context so requires.

We have requested the Lenders to make certain amendments to the Credit Agreement, and you have advised us that the Lenders are prepared and would be pleased to make the amendments so requested by us on the condition that we join in this Amendment.

Accordingly, in consideration of these premises, the promises, mutual covenants and agreements contained in this Amendment, and fully intending to be legally bound by this Amendment, we hereby agree as follows:

ARTICLE I

AMENDMENTS TO CREDIT AGREEMENT

Effective as of November 30, 2007, and subject to the fulfillment of the conditions contained in Article II of this Amendment, the Credit Agreement is amended in each of the following respects:

(a) The term “Loan Documents” shall, wherever used in the Credit Agreement or any of the other Loan Documents, be deemed to also mean and include this Amendment.

(b) Clause (vi) of the definition of “Eligible Borrowing Base Property” in Section 1.1 of the Credit Agreement is amended by deleting the words “and are not subject to any negative pledge in favor of any Person other than the Agent and the Lenders” therefrom.

(c) Schedule 1 to the Credit Agreement (Subsidiary Guarantors) is amended to read in its entirety as set forth on Annex 1 attached hereto.

(d) Schedule 1A to the Credit Agreement (Borrowing Base Pool) is amended to read in its entirety as set forth on Annex 2 attached hereto.

(e) Schedule 7.1(b) to the Credit Agreement (Capitalization) is amended to read in its entirety as set forth on Annex 3 attached hereto.

(f) Schedule 7.13 to the Credit Agreement (Legal Name; Jurisdiction) is amended to read in its entirety as set forth on Annex 4 attached hereto.

ARTICLE II

CONDITIONS PRECEDENT TO AMENDMENT

The Lenders’ agreement herein to amend the Credit Agreement as of the Amendment Date is subject to the fulfillment to the satisfaction of the Lenders of the following conditions precedent on or prior to such date:

(a) The Borrower shall have executed and delivered to the Agent a counterpart of this Amendment, which shall be in form and substance satisfactory to the Lenders;

(b) The Guarantor shall have acknowledged and consented to the provisions of this Amendment; and

(c) The Agent and the Majority Lenders shall have executed this Amendment.

ARTICLE III

REPRESENTATIONS AND WARRANTIES

The Borrower and the Guarantor hereby represent and warrant to you as follows:

(a) Representations and Warranties. Each of the representations and warranties made by the Borrower and the Guarantor, as applicable, to the Agent and the Lenders in the Credit Agreement and other Loan Documents, as applicable, was true, correct and complete when made and is true, correct and complete on and as of the date hereof with the same full force and effect as if each of such representations and warranties had been made by the Borrower and the Guarantor on the date hereof and in this Amendment, except to the extent that such representations and warranties relate solely to a prior date.

(b) No Defaults or Events of Default. No Default or Event of Default exists on the date hereof, after giving effect to this Amendment, and no condition exists on the date hereof which would, with notice or the lapse of time, or both, constitute a Default or an Event of Default under the Credit Agreement.

(c) Binding Effect of Documents. This Amendment has been duly authorized, executed and delivered to you by the Borrower and the Guarantor and is in full force and effect as of the date hereof, and the agreements and obligations of the Borrower and the Guarantor contained herein and therein constitute the legal, valid and binding obligations of the Borrower and Guarantor enforceable against the Borrower and Guarantor in accordance with their respective terms.

ARTICLE IV

MISCELLANEOUS

This Amendment may be executed in any number of counterparts, each of which when executed and delivered shall be deemed an original, but all of which together shall constitute one instrument. In making proof of this Amendment, it shall not be necessary to produce or account for more than one counterpart thereof signed by each of the parties hereto. Except to the extent specifically amended and supplemented hereby, all of the terms, conditions and the provisions of the Credit Agreement and each of the other Loan Documents shall otherwise remain unmodified, and the Credit Agreement and each of the other Loan Documents, as amended and supplemented by this Amendment, are confirmed as being in full force and effect, and the Borrower and the Guarantor hereby ratify and confirm all of its agreements and obligations contained therein, as applicable.

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If you are in agreement with the foregoing, please sign the form of acceptance on the enclosed counterpart of this Amendment, whereupon this Amendment, as so accepted by you, shall become a binding agreement between you and the undersigned.

Very truly yours,

FIRST POTOMAC REALTY INVESTMENT LIMITED
PARTNERSHIP  

By: First Potomac Realty Trust,
its sole general partner

By:   /s/ Barry H. Bass_  
Barry H. Bass, Chief Financial
Officer and Executive Vice
President

(Signatures continued on next page)

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[Consent to Amendment No. 2 to Secured Term Loan Agreement]

CONSENT OF GUARANTOR

FIRST POTOMAC REALTY TRUST (the “Guarantor”) has guaranteed the Obligations (as defined in the Guaranty by the Guarantor in favor of the Lenders and the Agent, dated as of August 7, 2007 (the “Guaranty”). By executing this consent, the Guarantor hereby absolutely and unconditionally reaffirms to the Agent and the Lenders that the Guarantor’s Guaranty remains in full force and effect. In addition, the Guarantor hereby acknowledges and agrees to the terms and conditions of this Amendment and the Credit Agreement as amended hereby (including, without limitation, the making of the representations and warranties and the performance of the covenants applicable to it herein or therein).

GUARANTOR:

FIRST POTOMAC REALTY TRUST

By:   /s/ Barry H. Bass_ 
Barry Bass, Executive Vice President and
Chief Financial Officer

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ACCEPTED AND AGREED AS OF
THE 30th DAY OF NOVEMBER, 2007:

KEYBANK NATIONAL ASSOCIATION,

Individually and as Administrative Agent

By:  /s/ Jason R. Weaver      
Name: Jason R. Weaver
Title: Senior Vice President

PNC BANK, NATIONAL ASSOCIATION,

Individually

By:   /s/ Timothy P. Gleeson_
Name: Timothy P. Gleeson
Title: Vice President

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Annex 1

Schedule 1

Subsidiary Guarantors

Aquia One, LLC
1434 Crossways Boulevard I, LLC
1434 Crossways Boulevard II, LLC
403 & 405 Glenn Drive, LLC
ACP East Finance, LLC
ACP East, LLC
AP Indian Creek, LLC
Columbia Holding Associates, LLC
Crossways Associates LLC
Enterprise Center I, LLC
First Snowden, LLC
FP Airpark AB, LLC
FP Chesterfield ABEF, LLC
FP Chesterfield CDGH, LLC
FP Gude, LLC
FP Hanover C, LLC
FP Hanover D, LLC
FP Prosperity, LLC
FP Van Buren, LLC
FPR Holdings Limited Partnership
Gateway Manassas I, LLC
Greenbrier/Norfolk Holding LLC
Greenbrier/Norfolk Investment LLC
GTC II First LLC
Indian Creek Investors, LLC
Kristina Way Investments LLC
Landover Owings Mills, LLC
Linden I, LLC
Newington Terminal Associates LLC
Newington Terminal LLC
Norfolk First LLC
Plaza 500, LLC
Rumsey/Snowden Holding LLC
Rumsey/Snowden Investment LLC
Snowden First LLC

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Annex 2

Schedule 1A

Borrowing Base Pool

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Annex 3

Schedule 7.1(b)

Capitalization

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Annex 4

Schedule 7.13

Legal Name; Jurisdiction

First Potomac Realty Trust, a Maryland real estate investment trust
First Potomac Realty Investment Limited Partnership, a Delaware limited partnership
1434 Crossways Boulevard I, LLC, a Delaware limited liability company
1434 Crossways Boulevard II, LLC, a Delaware limited liability company
403 & 405 Glenn Drive, LLC, a Virginia limited liability company
Crossways Associates LLC, a Delaware limited liability company
Enterprise Center I, LLC, a Delaware limited liability company
FP Airpark AB, LLC, a Virginia limited liability company
FP Chesterfield ABEF, LLC, a Virginia limited liability company
FP Chesterfield CDGH, LLC, a Virginia limited liability company
FP Gude, LLC, a Maryland limited liability company
FP Hanover C, LLC, a Virginia limited liability company
FP Hanover D, LLC, a Virginia limited liability company
FP Prosperity, LLC, a Virginia limited liability company
Gateway Manassas I, LLC, a Delaware limited liability company
Landover Owings Mills, LLC, a Delaware limited liability company
Linden I, LLC, a Delaware limited liability company
Newington Terminal Associates LLC, a Delaware limited liability company
FPR Holdings Limited Partnership, a Delaware limited partnership
Newington Terminal LLC, a Delaware limited liability company
Kristina Way Investments LLC, a Delaware limited liability company
Greenbrier/Norfolk Investment, LLC, a Delaware limited liability company
Rumsey/Snowden Holding LLC, a Delaware limited liability company
Rumsey/Snowden Investment LLC, a Delaware limited liability company
Snowden First, LLC, a Delaware limited liability company
Aquia One, LLC, a Delaware limited liability company
ACP East, LLC, a Maryland limited liability company
ACP East Finance, LLC, a Maryland limited liability company
AP Indian Creek, LLC, a Delaware limited liability company
FP Van Buren, LLC, a Delaware limited liability company
GTC II First, LLC, a Delaware limited liability company
Indian Creek Investors, LLC, a Maryland limited liability company
Norfolk First, LLC, a Delaware limited liability company
Plaza 500, LLC, a Delaware limited liability Company

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