The top US commander in Iraq authorised prisoner interrogation tactics including the use of dogs, stress positions and isolation, according to a government memo.
General Ricardo Sanchez, then senior commander of US forces in Iraq, signed the document in September 2003, approving 29 interrogation techniques.
ACLU lawyer Amrit Singh
The memo was obtained by the American Civil Liberties Union (ACLU) under the Freedom of Information Act. The group claims the measures far exceed the limits of acceptable practice.
"General Sanchez authorised interrogation techniques that were in clear violation of the Geneva Conventions and the Army's own standards," said ACLU lawyer, Amrit Singh. "He and other high-ranking officials who bear responsibility for the widespread abuse of detainees must be held accountable."
The memo allowed for the presence of muzzled military dogs during interrogations to "exploit Arab fear of dogs".
It permitted "environmental manipulation" which included making a room hot or cold or using unpleasant smells, as well as isolating a prisoner and disrupting normal sleep patterns.
Gen Sanchez said in the memo that some of the techniques would require his prior approval and has denied that he gave that approval. Many were banned a month later after intervention from military lawyers.
The ACLU claims the memo is central to the Abu Ghraib prison abuse scandal, which occurred during Gen Sanchez's time as commander, although investigators have concluded the abuses were not the result of US policy.
The union said 12 of the interrogation techniques he authorised "far exceeded limits established by the Army's own Field Manual". It has lawsuits pending against both Gen Sanchez and Defence Secretary Donald Rumsfeld, alleging direct responsibility for the torture and abuse of detainees in US military custody.