((a)) The Secretary of the Navy, under such regulations as he prescribes, may authorize any United States naval vessel or activity to furnish any of the following supplies or services, when in the best interests of the United States, on a reimbursable basis without an advance of funds if similar supplies and services are furnished on a like basis to naval vessels and military aircraft of the United States by the foreign country concerned:
((1)) Routine port services in territorial waters of the United States or in waters under United States control, including pilotage, tugs, garbage removal, line-handling, and utilities, to naval vessels of foreign countries.
((2)) Routine airport services, including landing and takeoff assistance, use of runways, parking and servicing, to military aircraft of foreign countries.
((3)) Miscellaneous supplies, including fuel, provisions, spare parts, and general stores, but not including ammunition, to naval vessels and military aircraft of foreign countries.
((4)) Overhauls, repairs, and alterations together with necessary equipment and its installation required in connection therewith, to naval vessels and military aircraft of foreign countries.
((b))
((1)) Routine port and airport services may be furnished under this section at no cost to the foreign country concerned where such services are provided by United States naval personnel and equipment without direct cost to the Navy.
((2)) When furnishing routine port services under this section to naval vessels of a foreign country, the Secretary may furnish such services without reimbursement if such services are provided under an agreement that provides for the reciprocal furnishing by such country of routine port services to naval vessels of the United States without reimbursement. When furnishing routine airport services under this section to military aircraft of a foreign country, the Secretary may furnish such services without reimbursement if such services are provided under an agreement that provides for the reciprocal furnishing by such country of routine airport services to military aircraft of the United States without reimbursement.
((3)) If routine port or airport services are furnished under this section by a working-capital fund activity of the Navy established under and such activity is not reimbursed directly for the costs incurred by the activity in furnishing those services by reason of paragraph (2), the working-capital fund activity shall be reimbursed for such costs out of operating funds currently available to the Navy.
((c)) Payments for supplies and services furnished under this section may be credited to current appropriations so as to be available for the same purpose as the appropriation initially charged.