A US Army investigation into the abuse at Abu Ghraib prison finds that the scandal was not just caused by a small circle of rogue soldiers but resulted from failure of leadership at the highest level of the US command in Iraq, The Washington Post reported Friday.

The Post report quoted anonymous officials as saying that the Army report, which runs some 9,000 pages and has not been completed, says a combination of leadership failings, confounding policies and absolute confusion at the prison led to the abuse.

The investigation report widens the scope of culpability from seven military policemen who have been charged with abuse to include nearly 20 low-ranking soldiers who could face criminal prosecution in military courts. No Army officers, however, are expected to face criminal charges.

The Army report also implicates five civilian contractors in the abuse, and the Army officials plan to recommend that their cases be sent to the Justice Department for possible prosecution in civilian courts, said the Post report.

The investigation, shepherded by Major General George R. Fay, is one of several into the abuse, which came widely known after hundreds of photographs surfaced depicting detainees in mock sexual pyramid and being intimidated by unmuzzled dogs.