18 U.S.C. § 3058

Whoever, belonging to the armed land or naval forces of a belligerent nation or belligerent faction and being interned in the United States, in accordance with the law of nations, leaves or attempts to leave said jurisdiction, or leaves or attempts to leave the limits of internment without permission from the proper official of the United States in charge, or willfully overstays a leave of absence granted by such official, shall be subject to arrest by any marshal or deputy marshal of the United States, or by the military or naval authorities thereof, and shall be returned to the place of internment and there confined and safely kept for such period of time as the official of the United States in charge shall direct.