27 CFR § 447.51 - Import certification and delivery verification.
Pursuant to agreement with the United States, certain foreign countries are entitled to request certification of legality of importation of articles on the U.S. Munitions Import List. Upon request of a foreign government, the appropriate ATF officer will certify the importation, on Form ITA-645P/ATF-4522/DSP53, for the U.S. importer. Normally, the U.S. importer will submit this form at the time he applies for an import permit. This document will serve as evidence to the government of the exporting company that the U.S. importer has complied with import regulations of the U.S. Government and is prohibited from diverting, transshipping, or reexporting the material described therein without the approval of the U.S. Government. Foreign governments may also require documentation attesting to the delivery of the material into the United States. When such delivery certification is requested by a foreign government, the U.S. importer may obtain directly from the U.S. District Director of Customs the authenticated Delivery Verification Certificate (U.S. Department of Commerce Form ITA-647P) for this purpose.