An independent US commission has found the abuse of inmates at Iraq's Abu Ghraib prison was mainly to be blamed on soldiers running the facility.
The world was shocked by the images of abuse that emerged
But US Defence Secretary Donald Rumsfeld and the Joint Chiefs of Staff also failed to exercise proper oversight, its report said.
The panel, led by former US Defence Secretary James Schlesinger, said the situation there was one of "chaos".
But the report said there was no official policy of abuse at the jail.
Mr Schlesinger said that while direct responsibility lay with commanders at local level, institutional and personal responsibility for the abuse lay right up the chain of command to Washington, including the most senior commander in Iraq at the time, Gen Ricardo Sanchez.
"The abuses were not just the failure of some individuals
to follow known standards, and they are more than the
failure of a few leaders to enforce proper discipline,"
the report said.
"There is both institutional and personal responsibility at higher levels."
The report did not suggest Mr Rumsfeld had ordered any of the abuses or did anything to encourage them.
But it indicated that his policies created some confusion at lower levels of the military.
During the press conference held to unveil the conclusions of the report, Mr Schlesinger and his colleagues on the four-person panel agreed Mr Rumsfeld could be "commended" for the way he approached the investigation.
Mr Schlesinger added, in answer to a question, that Mr Rumsfeld's resignation would be "a boon to all of America's enemies" and would be a "misfortune if it were to take place".
Neither did the panel think the Chairman of the US Joint Chiefs of Staff, General Richard Myers, should resign.
Still, that may not satisfy many of the Bush administration's critics and this report seems sure to re-ignite the debate over the scandal, says the BBC's Pentagon correspondent, Nick Childs.
Mr Schlesinger said the prison was for civilian inmates and was not suitable for the numbers eventually held there.
Mr Schlesinger also said the prison guards at the prison were undertrained for the task, under-equipped and constantly under attack.
He said that on the night shifts there was systematic "sadism" and he described the prison at those times as an "animal house".
"There were freelance activities on the part of the night shift at Abu Ghraib," he said. These activities included soldiers taking pictures.
The panel also included former Defence Secretary Harold Brown, former
Florida Republican Representative Tillie Fowler and retired Air Force
General Charles Horner, who led the allied air campaign in the 1991 Gulf War.
It was appointed by Mr Rumsfeld in May this year to look into the abuses which took place at the prison between October and December 2003.