Whoever, within the jurisdiction of the United States, goes upon any military, naval, or Coast Guard reservation, post, fort, arsenal, yard, station, or installation, for any purpose prohibited by law or lawful regulation; or

Whoever reenters or is found within any such reservation, post, fort, arsenal, yard, station, or installation, after having been removed therefrom or ordered not to reenter by any officer or person in command or charge thereof—

Shall be fined under this title or imprisoned not more than six months, or both.