Officials at MacDill Air Force Base said there is no indication the incident late Monday was an act of terrorism.
The man was with a woman in a car that tried to enter the base, which houses the U.S. command center for the wars in Afghanistan and Iraq.
Authorities say the pair tried to use fraudulent military identification. Security asked them to get out of the vehicle and searched the car. They found three rifles, three handguns and loads of ammunition in the sport utility vehicle.
Neither the man nor the woman involved have been identified. They are still being questioned.
