WASHINGTON — The Army private suspected of giving classified U.S. documents to the anti-secrecy group WikiLeaks was forced to sleep naked in a military jail at least once this week, the Marine Corps acknowledged Friday after the soldier's lawyer complained.

Commanders of the brig in Quantico, Va., ordered all of Pfc. Bradley Manning's clothing, including his boxer shorts, taken from him Wednesday night under provisions of the Navy Corrections Manual, which governs prisoner treatment, said 1st Lt. Brian Villiard, a spokesman for the Marine Corps base.

"It was a situationally driven event but to go into detail about it would be inappropriate because it would violate the detainee's privacy," Villiard said.

Col. Thomas V. Johnson, another Quantico spokesman, said the treatment was not punitive.

Manning, a former intelligence analyst, is charged with aiding the enemy and 33 other offenses for allegedly stealing computer files of more than 250,000 confidential State Department cables, classified video of a deadly U.S. helicopter attack and a raft of Iraq and Afghanistan war logs. The video and thousands of the documents have been published on the WikiLeaks website.

He was arrested in May and brought to Quantico July 29 from a detention facility in Kuwait.

The Navy Corrections Manual permits clothing removal for prisoners who have threatened suicide or made a suicidal gesture, or for strip searches involving suspicion of a crime. Villiard said Manning hadn't been placed on suicide watch.

The 23-year-old Crescent, Okla., native remains in maximum custody and on prevention-of-injury status — designations that keep him confined alone 23 hours a day, and require removal of all clothing except his boxer shorts at night.

Civilian defense attorney David Coombs wrote on his blog Thursday night that Manning had been inexplicably stripped of his clothing for seven hours Wednesday night.

"This type of degrading treatment is inexcusable and without justification. It is an embarrassment to our military justice system and should not be tolerated," Coombs wrote.

In January, after Manning was placed on suicide watch for two days, Coombs filed a complaint with the base commander alleging the brig commander broke military rules and ignored the brig's own psychiatrist's recommendation regarding Manning's mental state. Coombs contends the confinement conditions are punitive.

The United Nations torture investigator is pursuing an inquiry into Manning's confinement, based on allegations by a Manning supporter.

Manning's friend and frequent visitor David House, of Cambridge, Mass., said in a teleconference with reporters Wednesday that Manning's mental state has deteriorated during his more than eight months at Quantico.