An Army private charged with sending reams of classified information to the secret-busting website WikiLeaks testified Thursday that his jailers at a Marine Corps brig answered his complaints about "absurd" restrictions by tightening the screws.

Pfc. Bradley Manning testified on the third day of a hearing at Fort Meade, near Baltimore, to determine whether his treatment at the Quantico, Va., facility was so punishing that it warrants dismissal of his case. The hearing continues Friday with prosecutors likely to cross-examine the 24-year-old intelligence analyst.

Manning, speaking publicly for the first time since his May 2010 arrest, said he got so used to leg irons and being locked up 23 hours a day that when he was finally transferred to medium-security confinement at Fort Leavenworth, Kansas, in April 2011, he felt uneasy moving freely around the cell block.

"There was the sense of, `OK, I know they're going to put the hammer down on me soon,'" Manning said near the end of his five hours on the witness stand.

Besides being classified "maximum custody," Manning was subjected to additional restraints during his nine months at Quantico because he was either on suicide watch or considered at risk of hurting himself or others. Commanders maintained the extra restrictions despite repeated recommendations by brig psychiatrists that they be eased. They included scratchy, suicide-prevention bedding and sometimes having all his clothing, eyeglasses and reading material removed from his cell.

The military contends the treatment was proper.

Manning testified that he angered brig commander Chief Warrant Officer 2 Denise Barnes when he vented his frustration.

"There was a word, I think it was `absurd,'" he said. "That was my opinion of how I see the restrictions at that point."

Manning said he got frustrated spending up to 23 hours a day in a windowless, 6-by-8-foot cell.

"It was pretty draining," Manning said under questioning by defense attorney David Coombs.

At one point during his testimony, Manning donned a dark-green, suicide-prevention smock resembling an oversized tank top made of stiff, thick fabric. He said it was similar to one he was issued in March 2011, several days after Quantico jailers started requiring him to surrender all his clothing and eyeglasses each night as a suicide-prevention measure. This occurred after he told them _ out of frustration, he said _ that if he really wanted to hurt himself, he could have done so with his underwear waistband or flip-flops.

Before receiving the smock, he was forced to stand naked at attention one morning for a prisoner count, he said.

"I had no socks, no underwear, I had no articles of clothing, I had no glasses," he said.

The 5-foot-3 soldier looked youthful in his dark-blue dress uniform, close-cropped hair and rimless eyeglasses. He was animated, often speaking in emphatic bursts, swiveling in the witness chair and gesturing with his hands.

Manning was polite throughout his testimony, referring to his attorney as "sir" and making frequent eye contact with Coombs and the judge. Only after watching two videos of himself speaking to his guards while wearing only his boxers _ the first video shows him surrendering his clothes _ did his voice waver.

"It brings that back, the fact that I was there," Manning said of the video.

About 20 Manning supporters, many wearing black T-shirts with the word "truth," were in the courtroom. For the most part, the audience sat in rapt silence, although Manning got a laugh when he explained why he passed the time by making faces in the mirror: "The most entertaining thing in there was the mirror."

When testimony concluded, several supporters stood and urged Manning to "stay strong."

Some said they were impressed with his intellect, composure and military bearing.

"He's very respectful," supporter Bill Wagner said. "He comes across as a very likable fellow."

Another supporter, Kevin Zeese, said Manning's demeanor was at odds with the way he's been portrayed.

"The caricature is this meek, scared, sexually confused guy," Zeese said. "He comes off as this intellectual."

Earlier Thursday, the military judge, Army Col. Denise Lind, accepted the terms under which Manning may plead guilty to eight of the 22 charges he faces. Coombs revealed the plea offer in early November, saying it would enable Manning to take responsibility for sending U.S. secrets to WikiLeaks.

Lind hasn't formally accepted the pleas but has indicated she will consider them at a hearing starting Dec. 10.

Under the offer, Manning would plead guilty to certain charges as violations of military regulations rather than as violations of federal espionage and computer security laws. The offenses would then carry maximum prison terms totaling 16 years rather than 72.

The pleas would include admissions that Manning sent WikiLeaks classified memos, Iraq and Afghanistan war logs, Guantanamo Bay prison records and a 2007 video clip of a U.S. helicopter crew gunning down 11 men later found to have included a Reuters news photographer and his driver.

The government could still prosecute Manning for all 22 counts he faces, including aiding the enemy. That offense carries a maximum penalty of life in prison.