US Defence Secretary Donald Rumsfeld is being sued by two civil liberties group for allegedly authorising torture and then failing to stop it.
Donald Rumsfeld strongly disputes the claims
The American Civil Liberties Union and Human Rights First have filed a lawsuit on behalf of eight men who claim abuse by US forces in Iraq and Afghanistan.
The men allege they suffered beatings, mock executions and sexual humiliation.
The Pentagon says no policies or procedures Mr Rumsfeld approved were intended as abuse or condoning abuse.
"There have been multiple investigations into the various aspects of detainee abuse," it said in a statement. "None have concluded there was a policy of abuse."
The groups are seeking undetermined compensation for four Iraqis and four Afghans detained at various locations, including Iraq's Abu Ghraib prison and the Bagram air base in Afghanistan.
None of the men were ever charged and all have since been released, they said.
The case - being heard in Mr Rumsfeld's home state of Illinois - focuses on an order he signed in December 2002 authorising new methods for interrogating prisoners at Guantanamo Bay.
Both groups say the defence secretary later ignored overwhelming evidence that the policies resulted in prisoner abuse.
"Secretary Rumsfeld bears direct and ultimate responsibility for this descent into horror by personally authorising unlawful interrogation techniques and by abdicating his legal duty to stop torture," said lead counsel Lucas Guttentag.
The defence secretary has apologised for the abuse scandals and has twice offered to resign.
Three other cases are being heard against Lt Gen Ricardo Sanchez, former commander of US military forces in Iraq, Col Thomas Pappas an Brig Gen Janis Karpinski, both commanders at Abu Ghraib.