One of the accused soldiers in the Abu Ghraib abuse scandal has agreed a deal with prosecutors, his lawyer says.
Frederick said he had accepted responsibility for his role
Staff Sgt Ivan Frederick will plead guilty to some charges, and be acquitted on others, Gary Myers said.
Sgt Frederick accepted his responsibility amid "the corruptive procedure at Abu Ghraib", he added.
The judge in the case said senior US intelligence officers may be forced to testify whether the US defence department authorised the abuse.
Reservists Sgt Frederick, Sgt Javal Davis and Specialists Charles Graner and Megan Ambuhl are accused of various offences, including cruelty and maltreatment of prisoners, as well as assault and indecent acts.
The men are accused of piling naked Iraqi detainees on top of one another and jumping on them, as well as other violent and humiliating acts.
It is not clear to which charges Sgt Frederick has pleaded guilty, but Mr Myers said his sentence has already been agreed.
"He's taking responsibility for certain acts," he said.
Also on Tuesday, prosecutors said the defendants should not be allowed to call intelligence colonels Steven Jordan and Thomas Pappas to give evidence, as the officers may face charges themselves related to the abuse, and their testimony could affect their own trial.
Defence lawyers have urged the judge to remove their immunity from prosecution and force them to testify.
Judge Col James Pohl told lawyers he was inclined to agree that their evidence was "critical information to the
defendants... that this was condoned by the higher-ups".
He said unless the prosecution could convince him otherwise by 17 September, he would remove the colonels' immunity.
But Col Pohl rejected a defence attempt to subpoena US Defence Secretary Donald Rumsfeld to give evidence.
A lawyer for Sgt Javal Davis said Mr Rumsfeld had signed a document in 2002 authorising severe interrogation techniques on prisoners in Guantanamo Bay, Cuba.
He said the methods included the hooding of prisoners, and long periods of interrogation and isolation, and were later adopted at Baghdad's Abu Ghraib.
"It also includes nudity and inducing stress, and as an example, it includes dogs," lawyer Paul Bergrin told the court.
Col Pohl rejected the subpoena request, saying: "I fail to see a connection between this group and the
authorities in Washington. I'm not saying there is no link, but you have not shown sufficient evidence."
Sgt Davis' lawyer tried to have Rumsfeld summoned
He did say the defence could re-submit the request if it came up with more evidence.
On Tuesday, Sgt Davis admitted that he initially lied
by saying he did not take part in the maltreatment, because he was tired and wanted to end the interview.
"I was dishonest about the things I was accused of,"
he told the hearing at a US military barracks in
Mannheim. "I wanted to maintain my integrity."
The hearing preceded the scheduled release of a report in the US on Tuesday on the Abu Ghraib affair, which was expected to be critical of Mr Rumsfeld and other senior Pentagon officials.