The FBI was investigating after a civilian was arrested with explosives in his vehicle on an Army base in Georgia that is headquarters to the service's global communication and information systems, authorities said Wednesday.
Military authorities were not treating the case as a terrorist threat, said Buz Yarnell, a spokesman for Fort Gordon near Augusta.
The arrest Tuesday came a day after an AWOL serviceman was arrested in Florida for trying to enter an Air Force base there with fake ID and weapons, although authorities did not link the two and the Florida case was also deemed not terrorism.
Yarnell gave few other details. A news conference was scheduled at Fort Gordon later Wednesday.
Yarnell said a search of the civilian's vehicle Tuesday uncovered a knapsack containing military hand grenades. He said the man arrested is a suspect in a theft of military equipment from Fort Gordon in April.
FBI spokesman Steve Emmett in Atlanta said federal charges are forthcoming but he does not expect them to involve explosives or terrorism. Agents with the Bureau of Alcohol, Tobacco, Firearms and Explosives are also investigating.
Yarnell says the vehicle was parked in a remote area when it was discovered. He says it did not pose a threat to command operations or military housing.
Fort Gordon is the home of the Army Signal Corps and the Eisenhower Army Medical Center, one of largest military hospitals in the Southeast.