Another of the military officials who oversaw WikiLeaks suspect Bradley Manning's detention at a Virginia military prison testified Friday that he was kept on suicide watch for his own protection, never to "punish" him.

Chief Warrant Officer 2 Denise Barnes said that shortly after Manning's arrival to the brig at Quantico, she made the decision to keep him on a 24-hour suicide watch.

She testified that she also gave the order that Manning would have to sleep naked in his jail cell every night, after he made a remark that led her to fear he might use his clothing to take his own life.

Manning, 24, is on trial for leaking a trove of military and diplomatic documents to the anti-secrecy website WikiLeaks, run by Julian Assange.

Barnes is the second prison official in as many days to testify that, far from trying to torment the young army private during his nine-month long detention there, she had Manning's well-being at heart.

On Thursday, James Averhart, the official in charge of the Marine Corps brig at Quantico, said the suspect was held as a "maximum security prisoner" for his own safety.

While in custody at the Virginia marine base, Manning was held under 24-hour suicide watch in a tiny cell and allowed only 20 minutes of sunlight a day.

He was stripped of almost all his clothes at night under strict "prevention of injury" guidelines that military commanders contend were put in place to keep him from harming himself.

His attorneys say the conditions of his detention at Quantico were tantamount to "unlawful pretrial punishment," and were so egregious that the case against him should be dismissed.

Barnes said she developed a fairly good rapport with the inmate.

"We would talk about food, basketball," she said in court.

But she said she was also worried about a sudden change in his demeanor.

"It really shocked me," Barnes said. "At the beginning he was looking at me, joking, laughing."

The much more reserved and stoic affect that Manning later developed surprised her, Barnes said, since earlier "he would have engaged the conversation." This change, she explained, was one reason for not lifting the suicide watch.

Manning was serving in Iraq as a US army intelligence analyst when he was arrested in May 2010. He was sent briefly to a US jail in neighboring Kuwait, before being transferred to the Quantico jail.

After nine months there, he was transferred to a US Army prison at Fort Leavenworth, Kansas, in April 2011.

The army private could spend the rest of his life in prison if he is convicted of the charges against him in the case, which include "aiding the enemy," chiefly Al-Qaeda. The case is expected to go to trial in March.