The panel did not find that Rumsfeld or military leaders directly ordered abuse such as stripping prisoners naked and sexually humiliating them.
It said, however, that the abuses were not carried out by just a few individuals, as the Bush administration has consistently maintained.
Schlesinger said there were 300 cases of abuses being investigated, many beyond Abu Ghraib. "So the abuses were not limited to a few individuals."
He said there was "sadism" by some Americans at Abu Ghraib.
"It was a kind of animal house on the night shift" at the jail, he added.
The report said prisoner interrogation policies in Iraq were inadequate and deficient, and changes made by Rumsfeld between December 2002 and April 2003 in what interrogation techniques were permitted contributed to uncertainties in the field as to what actions were allowed and what were forbidden.
The report said an expanded list of more coercive techniques that Rumsfeld allowed for Guantanamo "migrated to Afghanistan and Iraq, where they were neither limited nor safeguarded."
The Schlesinger panel, named by Rumsfeld in May to look into the abuse and how effectively the Pentagon addressed it, also includes former Defence Secretary Harold Brown, former Florida Republican Rep Tillie Fowler and retired Air Force Gen Charles Horner, who led the allied air campaign in the 1991 Gulf War.
Echoing an earlier investigation headed by Army Maj Gen Antonio Taguba, the Schlesinger panel said the "weak and ineffectual leadership" of Army Brig Gen Janis Karpinski, commander of the 800th Military Police Brigade at Abu Ghraib, "allowed the abuses at Abu Ghraib".
In a statement released by the Pentagon, Rumsfeld said the panel provided "important information and recommendations that will be of assistance in our ongoing efforts to improve detention operations."
In addition, a separate Army investigation headed by Maj Gen George Fay faulted Lt Gen Ricardo Sanchez, at the time the top US commander in Iraq, for leadership failures for not addressing troubles at Abu Ghraib, a senior Army official said. The Schlesinger panel, too, faulted Sanchez.
The Fay report, to be released on Wednesday, found Sanchez and his staff were preoccupied with combating an escalating insurgency and did not focus on the festering problems at Abu Ghraib, the Army official said.
The report also found that Army military intelligence soldiers kept a number of prisoners, dubbed "ghost detainees," off the books and hidden from the International Committee of the Red Cross, the official added. It also found a small number of military police used dogs to menace teen-age Abu Ghraib detainees.
Seven Army reservists from the 372nd Military Police Company already have been charged with abusing prisoners at Abu Ghraib. The Fay report implicates about two dozen more low-ranking soldiers, medics and civilian contractors in the Abu Ghraib abuse, and about half of them will be recommended for criminal proceedings, the Army official said.
"These are illegal, unauthorized, mischievous, sadistic activities happening outside the purview of interrogations," the Army official said.
However, the Fay report maintains that the abuse was perpetrated by a few soldiers, but went unchecked as a result of military leadership deficiencies, the Army official said.
White House spokesman Scott McClellan told reporters in Crawford, Texas, "Remember, we said early on that it's important that those who were responsible for the appalling acts at Abu Ghraib are held accountable. And it's also important to take a broad look and make sure that there are no systemic problems."
In Mannheim, Germany, a US military judge ruled that Rumsfeld could not be forced to testify in the court martial of a sergeant charged in the abuse.
- REUTERS
The full report:
Independent Panel to Review DoD Detention Operations
[PDF 126 pages]
Herald Feature: Iraq
Related information and links
