Defense Secretary Donald H. Rumsfeld broadly apologized today for the abuses of Iraqi prisoners in U.S. custody and sent a sharp warning that "many more" images and videos exist depicting violence on the captives.

In hearings today on Capitol Hill, Rumsfeld said the materials could only be described as "blatantly sadistic, cruel and inhuman."

He also acknowledged that he "failed to understand" the importance of alerting President Bush and lawmakers earlier to the brutal acts at the prison. When asked whether he should step down over the scandal, the hard-charging Rumsfeld uncharacteristically paused.

"Needless to say, if I could not be effective, I would resign in a minute," he said. "I would not resign simply because people try to make a political issue out of it."

In straightforward testimony to the Senate and then the House that lasted about 6 hours, Rumsfeld occasionally flashed his trademark combativeness. He said he should be held accountable for the abuses at the Iraqi prison and offered several reforms, including compensation for victims who were abused.

In a sweeping apology that included mistreated Iraqis, President Bush, the Congress, the U.S. military, and the American people, Rumsfeld said, "These events occurred on my watch. As secretary of Defense, I am accountable for them and I take full responsibility."

He added: "I feel terrible about what happened to Iraqi detainees. They are human beings. They were in U.S. custody. Our country had an obligation to treat them right. We didn't and that was wrong."

In sworn statements to the House Armed Services Committee this afternoon, one lawmaker said events have dissolved the trust not only between the Arab world and U.S. forces, but also between the U.S. Congress and the Department of Defense.

Minutes into his testimony, Rumsfeld was heckled by several people in the audience, who shouted "Fire Rumsfeld!" and "War Criminal!" Security guards ushered the protesters out of the room.

Rumsfeld offered several reforms in hopes of containing fallout from the abuses that has led some Democratic leaders to call for his resignation and sharp criticism from Republicans. Investigations have shown that 25 prisoners in Iraq have died while in custody, said Les Brownlee, the acting Army secretary. Of those, a dozen died from natural causes, but two have been declared homicides and 10 remain under investigation.

Rumsfeld said he is forming an independent commission, composed of former officials, to determine whether more investigations need to be launched besides the several underway by the Pentagon. The commission will be expected to make its conclusions within 45 days.

Moreover, Rumsfeld said the procedures for detainees would be reviewed and said that victims also should receive some form of remediation. And the Defense secretary, under questioning from senators, said he would consider tearing down the Abu Ghraib prison where the abuses occurred under U.S. command. During the regime of Saddam Hussein, the prison was used for torturing and executing Iraqis.

Lt. Gen. Lance Smith testified before the House that about 75% of the recommendations made from a military report on the abuses have been implemented.

Rumsfeld, following Bush's lead as the furor has drawn more international outrage, elaborated before the senators on his apology for the abuses at the Iraqi prison.

"To those Iraqis who were mistreated by members of the U.S. armed forces, I offer my deepest apology. It was inconsistent with the values of our nation, it was inconsistent with the teachings of the military to the men and women of the armed forces, and it was certainly fundamentally un-American."

The Defense secretary today had two missions: to explain how the abuses occurred and to save his job. His sworn testimony, carried on live television in the U.S. and at least two Arab networks, comes a week after photographs of naked and abused Iraqi prisoners produced waves of anger around the world and drew condemnation of the U.S.-led occupation in Iraq.

Rumsfeld's appearance before the Senate Armed Services Committee this morning and its House counterpart this afternoon came under mounting pressure from lawmakers to report in greater detail about abuses of Iraqi prisoners in U.S. custody.

Throughout his testimony, Rumsfeld emphasized that the military was the first to announce that abuses had occurred at Abu Ghraib, that investigations had been launched, and that "swift, corrective action" was implemented.

The hearing did not break down along partisan lines, with some of the staunchest support for Rumsfeld coming from Democrats.