Baghdad, Iraq ? A U.S. Army staff sergeant pleaded guilty Wednesday to abusing Iraqi detainees at Abu Ghraib prison, telling a military court that prisoners were forced to submit to public nudity and degrading treatment “for military intelligence purposes.”

Army reservist Ivan “Chip” Frederick, 38, of Buckingham, Va., confessed to eight counts of conspiracy, dereliction of duty, maltreatment of detainees, assault and committing an indecent act. He was expected to be sentenced today and could receive 11 years in prison.

A military policeman who is a corrections officer in civilian life, Frederick is the highest-ranking soldier charged in the scandal, which broke in April with the publication of photos and videos showing American troops abusing and humiliating naked Iraqi detainees.

His lawyer, Gary Myers, said Frederick agreed to cooperate fully in further investigations and would testify at courts-martial for other soldiers.

“I was wrong about what I did, and I shouldn’t have done it,” Frederick told the judge, Army Col. James Pohl. “I knew it was wrong at the time because I knew it was a form of abuse.”

But Frederick also blamed his chain of command, saying he was given no training or support in supervising detainees and only learned of regulations against mistreatment after the abuses occurred between October and December last year.

He testified that when he brought issues up with his commanders, “they told me to do what MI told me to do,” referring to military intelligence.

During the proceeding, Chief Warrant Officer Kevin Kramer, a military intelligence soldier called as a witness, referred to an e-mail from the U.S. command in Baghdad telling him to order his interrogators to be tough on prisoners.

“The gloves are coming off, gentlemen, regarding these detainees,” said the e-mail, which was read into evidence. It added that the command “wants the detainees broken.”

Frederick said that from his first day at the prison, he saw detainees “naked, handcuffed to their door, some wearing female underclothes.” He said the first time he witnessed sexual humiliation used as an interrogation technique came late last October when he saw intelligence officers handcuff naked prisoners together.

“Nudity was to humiliate and degrade them for military intelligence purposes. It was very embarrassing for an Arabic male to be seen nude by another,” Frederick said.

During an incident last Nov. 4 captured on photos transmitted around the world, Frederick said he helped hook wires on a detainee’s hands and told him he would be electrocuted if he fell off a box. An Army investigator encouraged him to abuse the detainee, saying he didn’t care what was done to the prisoner “as long as you don’t kill him,” Frederick said.

In a Nov. 8 incident, Frederick admitted, detainees were strip-searched and remained naked, even after female soldiers arrived on the scene — which is against military rules, he said.

Frederick also said soldiers lined the detainees naked against a wall with bags on their heads and then forced three of them to masturbate.