In providing for the procurement of any agricultural commodity or product thereof available for disposition under the Food for Peace Act, as amended [
7 U.S.C.
1691 et seq.], for transfer by grant under this chapter to any recipient country in accordance with its requirements, the President shall, insofar as practicable and when in furtherance of the purposes of this chapter, authorize the procurement of such agricultural commodity only within the United States except to the extent that such agricultural commodity is not available in the United States in sufficient quantities to supply emergency requirements of recipients under this chapter.