The army's inspector-general made the revelations on Thursday in a long-awaited report made public at a hastily called Senate hearing.
The Defence Department had refused until now to give the total number of abuse allegations since the Iraq Abu Ghraib prison abuse scandal shocked the world three months ago.
The inspector-general report, ordered on 10 February after US occupation soldiers were found to have sexually humiliated and tortured detainees in Iraq, claimed that there were no systemic problems that contributed to the abuse. In some cases, the report found, the abuse was abetted or facilitated by officers not following proper procedures.
In contrast to its own findings, however, the army report also cites a February report from the International Committee for the Red Cross that said that "methods of ill treatment" were "used in a systematic way" by the US occupation in Iraq.
Senator John Warner, the Republican chairman of the Senate Armed Services Committee, who had been pressing for the results of the inspector-general report for several weeks, called a last-minute hearing on Thursday before Congress leaves for the rest of the summer on Friday.
The Army has not yet made the entire report public but released parts during the public hearing.
There are also accusations that
soldiers sodomised Iraqi boys
Acting Army Secretary Les Brownlee, testifying before a hastily called Senate Armed Services Committee hearing, said he accepted responsibility for the abuses committed by soldiers.
But Senator Carl Levin, ranking Democrat on the committee, said it was "difficult to believe there were not systemic problems with our detention and interrogations operations".
The army inspector-general report found that since the autumn of 2001, overall the United States had held more than 50,000 prisoners in Afghanistan and Iraq, a number never before made public.