"From 25 July 2003 to February 2004, 27 ... (military intelligence) personnel allegedly requested, encouraged, condoned or solicited military police personnel to abuse detainees and/or participated in detainee abuse and/or violated established interrogation procedures and applicable laws and regulations during interrogation operations at Abu Ghraib," the report said.
Pentagon officials released to key lawmakers in the US Congress the internal report by General George Fay investigating abuses of Iraqi inmates during interrogations by military police.
"We discovered serious misconduct and a loss of moral values," said Gen. Paul Kern, the head of the investigation, while briefing reporters at the Pentagon.
Kern and other officials detailed the results of the investigation, commonly called the Fay report, after one of the chief investigators.
Of the 27 individuals, 23 were members of the military personnel and four were contractors. Another eight, including two contractors, knew of abuse and failed to report it, Kern said.
The four contractors working with them committed acts in 44 instances of prisoner abuse that could prompt criminal charges, the report also found.
'Inhumane to sadistic'
The Army report found "misconduct ranging from inhumane to sadistic by a small group of morally corrupt soldiers and civilians," a lack of discipline on the part of a military intelligence unit at Abu Ghraib and "a failure or lack of leadership" by the U.S. military leadership in Iraq, headed by Lt. Gen. Ricardo Sanchez, the former top US commander in Iraq.
"Most, though not all, of the violent or sexual abuses occurred separately from scheduled interrogations and did not focus on persons held for intelligence purposes," the report stated.
The release of the investigation's findings came just one day after another independent probe concluded that leadership failures at the top levels of the Pentagon contributed to the chaotic environment in which detainees were abused.
The blue-ribbon panel headed by former defense secretary James Schlesinger on Tuesday cited leadership shortcomings among the Joint Chiefs of Staff and the military command in Iraq that contributed to the abuse at Abu Ghraib.