A soldier who guarded suspected terrorists at the U.S. naval base in Guantanamo Bay, Cuba, has disappeared, U.S. military officials said Thursday.

Also Thursday, U.S. military officials announced that Army Maj. Gen. Geoffrey D. Miller will assume control of the detention mission next month.

Miller, currently stationed in Seoul, South Korea, will replace Gen. Rick Baccus, who was the second general in the post since detainees began arriving at the base in January.

Army Staff Sgt. Ryan Foraker, 31, of Logan, Ohio, was last seen on Tuesday at about 1:30 a.m. leaving his quarters at Camp America, near the Camp Delta prison where 598 detainees are held, Lt. Col. Bill Costello said.

Foraker's civilian shorts, T-shirt and wallet were found outside the fence of Camp America.

"There's no sign of foul play or suicide," Costello said.

Foraker's wife said Thursday night from her Logan home that everything seemed normal when she talked with her husband by telephone Monday afternoon.

Angela Foraker, 24, said the Army told her he might have disappeared after going swimming in the ocean. But she doubts that would have happened.

"He was afraid of heights. He didn't like the ocean waves. He wouldn't have gone swimming alone," she told The Associated Press in a phone interview.

The U.S. soldiers in Cuba are holding detainees accused of links to Afghanistan's fallen Taliban regime or the Al Qaeda terror network. Some detainees have reportedly spat on guards or thrown feces at them.

Costello dismissed suggestions that the detainees had anything to do with the disappearance and said Foraker had never been disciplined or showed signs of stress.

It is the first time a soldier has vanished since the detention mission began in January on the remote outpost, isolated by a sea infested with sharks and a Cuban government fence.

Officials have searched surrounding waters but have found no sign of Foraker. Costello said they were checking with the dive shop and boat companies to see if he had made any arrangements for rentals.