35 USCS Sect. 104

U.S. Patent Act

..Part II. Patentabililty of Inventions and Grant of Patents

....Chapt. 10. Patentability of Inventions

Sect.104. Invention made abroad

In proceedings in the Patent and Trademark Office and in the courts, an applicant for a patent, or a patentee, may not establish a date of invention by reference to knowledge or use thereof, or other activity with respect thereto, in a foreign country, except as provided in sections 119 and 365 of this title [35 UCSC Sects. 119, 365]. Where an invention was made by a person, civil or military, while domiciled in the United States and serving in a foreign country in connection with operations by or on behalf of the United States, he shall be entitled to the same rights of priority with respect to such invention as if the same had been made in the United States.