27 CFR 447.46: Articles in transit.

Articles subject to the import permit procedures of this subpart which enter the United States for temporary deposit pending removal therefrom and such articles which are temporarily taken out of the United States for return thereto are regarded as in transit and considered neither imported nor exported under this part. Such transactions are subject to the Intransit or Temporary Export License procedures of the Department of State (see 22 CFR part 123) or the entry clearance requirements for temporary imports maintained by the Department of Commerce (see 15 CFR 758.10).