WASHINGTON – More than two dozen soldiers and contractors attached to a military intelligence unit at Abu Ghraib prison in Iraq approved or took part in abuses of Iraqi detainees, an Army investigation has found in one of the most comprehensive looks to date at the scandal that damaged America’s image around the world.

A few of the abuses amounted to torture, Major General George Fay, one of the chief investigators, said yesterday.

“This is clearly a deviation from everything we’ve taught people on how to behave,” said General Paul Kern, who oversaw the investigation. “There were failures of leadership, of people seeing these things and not correcting them. There were failures of discipline.”

Officers in charge of the prison were negligent in the training and management of their troops, and some may face criminal charges, Army officials said. Until now, only seven lower-ranking military police soldiers have been charged.

In Philadelphia, the Democratic presidential candidate, John Kerry, repeated his call for Defense Secretary Rumsfeld to resign and for President Bush to appoint an independent commission.

“Harry Truman had that sign on the desk and it said, ‘The buck stops here,'” Mr. Kerry said. “The buck doesn’t stop at the Pentagon.”

The White House has blamed the scandal on a group of rogue soldiers who it said were acting on their own.

The new report identifies 27 people attached to the 205th Military Intelligence Brigade, which oversaw interrogations at Abu Ghraib, who are accused of complicity in the abuses. Of those, 23 are soldiers and four were civilian contractors working for the unit.

The investigation report says the violent and sexual abuses – particularly those captured in the now-famous pictures of naked and frightened prisoners – were mostly the work of a group of guards and military intelligence personnel who were not conducting interrogations but instead amusing themselves.

The report distinguishes this group of abuses from mistreatment committed during actual interrogations, which also occurred.

Some 15 of 23 soldiers from the 205th who are accused of abuse were interrogating prisoners and wrongly believed they were using approved techniques to question them, Army officials said. One such unapproved technique was interrogating a detainee naked, the report said.

The Army’s findings appear to widen to more than 50 the number of people who may face charges or disciplinary action for the abuses at Abu Ghraib. Criminal allegations against civilian contractors will be referred to the Justice Department for possible prosecution.

Investigators recommended that five officers with command responsibilities, including Colonel Thomas Pappas, commander of the 205th, and Lieutenant Colonel Stephen Jordan, director of the Abu Ghraib interrogation center, face possible disciplinary action, Army officials said.

While these individuals did not directly take part in abuses, their poor leadership contributed to the conditions that allowed them to occur, officials said.

The seven members of the 800th Military Police Brigade, which supplied the guards at the prison, have been charged in connection with the abuses seen in the photos. In addition, six soldiers in the 205th and two other contractors witnessed the abuse but failed to report it, General Kern said.

The report said investigators discovered three more MPs who took part in abuses, and one more who knew of the mistreatment and did not report it. It also noted that two medics knew of the abuses but did not report them.

Most of the people are not identified in the investigation report. All of them may face charges or disciplinary action for abuses that occurred between late July 2003 and early February 2004. “We discovered serious misconduct and a loss of moral values,” General Kern said.

The report blames the abuses on several factors: “misconduct…by a small group of morally corrupt soldiers and civilians, a lack of discipline on the part of leaders and soldiers,” and a “failure or lack of leadership” by higher command in Iraq.

General Kern said Lieutenant General Ricardo Sanchez, the senior U.S. officer in Iraq when the abuses occurred, was responsible for “the things that did or did not happen” but not directly culpable for the abuse. The lead investigators were General Fay and Lieutenant General Anthony Jones.

The Army’s investigation recorded 44 separate incidents of abuse, including one that led to the death of a prisoner, officials said. Army officials credited the military with fixing many problems outlined in the report and said the vast majority of military personnel in Iraq are doing their jobs honorably.