Defense Secretary Donald Rumsfeld (search) told lawmakers Friday he was sorry for not informing them about the abuse of Iraqi prisoners at Abu Ghraib prison and he offered a personal apology to those Iraqis who had suffered abuse.

"These events occurred on my watch as secretary of defense, I am accountable for them and I take full responsibility," Rumsfeld said. "To those Iraqis who were mistreated by the U.S. armed forces, I offer my deepest apology."

Rumsfeld made his comments under oath first before the Senate Armed Services Committee and later to the House Armed Services Committee.

Faced with an exploding scandal surrounding the abuse and the disclosure of graphic photographs, the defense secretary said he is assembling a group to independently probe the abuses and is seeking a way to provide compensation to those Iraqis abused.

"It's the right thing to do," he said. In a prepared statement read at the start of the hearings, Rumsfeld said, "Any wrongdoers need to be punished, procedures evaluated, and problems corrected."

The pictures "have offended and outraged everyone in the Department of Defense," Rumsfeld said in his testimony, adding that he wished he could have "conveyed the gravity" of the situation to Congress and the American people before photographs of the abuse were splashed across television screens.

"I failed to recognize how important it was to elevate a matter of such gravity to the highest level, including the president and the Congress," Rumsfeld said early in his testimony, which was interrupted briefly by protesters in the hearing room who called for him to be fired.

"This was a political and public relations Pearl Harbor," said Rep. Tom Cole, R-Okla., expressing a widely shared sentiment.

Some Democrats have called for him to resign, although President Bush said Thursday he had no intention of giving Rumsfeld a pink slip.

Rumsfeld was asked by Sen. Lindsay Graham, R-S.C., if he thinks he can continue his duties as secretary of defense.

"Certainly since this firestorm has been raging, it's a question I've been giving a lot of thought to. The key question to me is … whether or not I can be effective," Rumsfeld said. "Needless to say if I felt I couldn't be effective, I'd resign in a minute. I would not resign simply because people try to make a political issue out of it."

But when later asked by Sen. Evan Bayh, D-Ind., asked Rumsfeld: "Even though you weren't personally involved in the underlying acts here, would it serve to demonstrate how seriously we take this situation, and therefore help to undo some of the damage to our reputation, if you were to step down? "

"That's possible," the secretary responded.

More Photos, Videos of Abuse Exist

The military had been investigating reports of abuse at Abu Ghraib (search) since January.

• Raw Data: Pentagon's Jan. 16 News Release Announcing Investigation into Alleged Prison Abuses

"I wish we had known more sooner and been able to tell you more sooner but we didn't," Rumsfeld said.

The world should "watch us by our actions" to correct the mistakes, he said.

"We will strive to do our best, as imperfect as it may be," Rumsfeld said.

But the secretary and Gen. Richard Myers, chairman of the Joint Chiefs of Staff, said some of the slow flow of information was necessary because several military organizations were investigating it as a criminal matter.

"No one is stalling or covering up information but it's absolutely essential to protect the integrity of our justice system," Myers said. But "those found guilty will receive punishments based on their offenses."

The Defense officials also offered a warning to committee members: many more photographs and even some videos exist. So far, no videos have been aired in public.

"If these are released to the public, obviously it's going to make matters worse," Rumsfeld said.

Facilitating the 'Efforts of Our Enemy'

Lawmakers and Defense officials acknowledged that the controversy has hurt America's position in the War on Terror.

The reports of abuse "undermine the substantial gains — and I emphasize, the substantial gains — toward the goal of peace and freedom in various operation areas throughout the world, especially in Iraq," said Senate Armed Service Committee Chairman John Warner, R-Va.

"Our troops are less secure and our nation is less secure because these ... despicable actions fuel the rage and fury of those who hate us," said Sen. Carl Levin of Michigan, the ranking Democrat on the committee. "Our greatest as a nation are the moral values we stand for; those values have been compromised."

House members echoed the point in a hearing following the Senate session.

"I think you'd all agree the good name of America has been hurt and hurt badly by these revelations," said Rep. John Spratt, D-S.C.

Air Force Lt. Gen. Lance Smith, deputy commander of U.S. Central Command, said the actions of the perpetrators have "facilitated the efforts of our enemy … and gives weight to the charge of American hypocrisy."

But "commanders are taking action both to make sure justice is done and to make sure this kind of deplorable conduct will not be repeated," Smith said.

Army Chief of Staff Gen. Peter Schoomaker, who is ultimately in charge of training all troops, said, "I take it personally when any of them fall short of our standards."

"What we are dealing with are actions of a few. These are conscious issues against all that we stand for. This is not a training issue but one of loyalty and values," he said.

'They Weren't Hiding Anything'

"I wanna know how far up the chain you're willing to go" to find those responsible, and if that will include anyone who suggested the actions be taken against the prisoners, Levin asked Rumsfeld.

"That's exactly why the investigation was initiated ... we'll find what their recommendations are" as far as prosecution, Rumsfeld replied.

Democratic Sens. Ted Kennedy of Massachusetts and Robert Byrd of West Virginia asked why no one heard about the investigation until the pictures surfaced.

"Why are the president and his advisers only now publicly condemning the prisoner abuses in Iraq when apparently the Defense Department has known about them for months?" Byrd asked. "I don’t recall hearing a peep from you."

Rumsfeld repeatedly pointed out that Centcom reported in January that investigations into abuse were ongoing.

"They weren't hiding anything, they disclosed it to the world," Rumsfeld said. "The idea that this was a story broken by the media is simply not a fact … what's not known is that classified photographs would be given to the press before they were given to the Pentagon."

Rumsfeld said he and most defense officials, as well as Bush, were "blindsided" when they saw the photos on television.

The Story Unfolds

Rumsfeld was told of the pictures on Jan. 13, when one of the military police told his story and provided Centcom copies of the photos, a Defense official told Fox News.

Investigations began in Iraq the following day. Rumsfeld ordered a broad overview into Abu Ghraib and other facilities in Iraq, and of procedures and training. This turned into six independent investigations.

On April 20, CBS alerted Pentagon officials that it had several of the incriminating photos, the official told Fox News. Within the next few days, calls were put into the White House at the "staff level," and Centcom chief Gen. John Abizaid expressed distress over the timing of the photos, since conflicts were erupting in Fallujah, as well as Shiite strongholds south of Baghdad.

Myers approached CBS' Dan Rather to make a case for holding the story until the situation on the ground cooled down.

"My conclusion was, this was the worst possible time for this to come forward," Myers said Friday.

Rumsfeld was not briefed about CBS' possession of the photos until the day '60 Minutes II' was to air, April 28. It was then that top congressional leaders were informed.

Two days later, coalition forces commander Gen. Ricardo Sanchez approved the 'Taguba Report' on the goings on at Abu Ghraib, initiating its climb up the command chain.

Fox News' Bret Baier and Ian McCaleb contributed to this report.