The US military has barred a number of interrogation methods in Iraq, defence officials in Washington say.
The scandal over prisoner abuse has damaged the US case for war in Iraq (AP/Courtesy The New Yorker)
The banned methods include sleep and sensory deprivation, and making prisoners assume "stress positions".
The US military has been rocked by revelations about abuse at Baghdad's Abu Ghraib prison.
Friday saw the army report that a fourth US soldier would soon face a court martial for allegedly mistreating Iraqi inmates.
Prohibited interrogation methods now include depriving prisoners of sleep for more than 72 hours, placing hoods over their heads or making them kneel or stand uncomfortably.
Such methods were approved by the Pentagon in September - although they could only have been used with the permission of the top US commander in Iraq.
A US military official said such permission was never given.
The rules regarding interrogations came to light as part of congressional inquiries into the abuse scandal.
Several Democratic senators, as well as human rights activists, have said the methods breached the Geneva Convention, which outlaws the physical or moral coercion of prisoners.
Defence officials have, however, strenuously denied that charge, saying all the techniques were legal.
"There's an enormous amount of subjectivity in the
interpretation of the Geneva Conventions," Pentagon spokesman Lawrence Di Rita said.
The change in policy came as the army said
Military Police Cpl Charles A Graner would appear before a court on Thursday.
He is due to enter a plea on charges including cruelty and maltreatment of detainees.
Seven soldiers, including England and Graner, face charges
One abuse suspect, Jeremy Sivits, has made detailed allegations about his colleagues, including Cpl Graner.
Staff Sergeant Ivan Frederick and Sergeant Javal
Davis will also appear before the court on Thursday, facing five charges each.
Specialist Jeremy Sivits becomes the first to go on trial on Wednesday.
Seven soldiers have so far been charged over abuse at the jail - three are still waiting to hear if they will face trial.
They include Private Lynndie England, who is pregnant with Cpl Graner's child.