WASHINGTON - President Bush is standing by Defense Secretary Donald Rumsfeld as both men brace for the anticipated release of more pictures and video images showing Iraqi prisoners being abused by American soldiers.

Bush, who is facing eroding confidence in senior military ranks and declining credibility abroad, visits the Defense Department today for a previously scheduled briefing that takes on new significance because of the torture and sexual humiliation of prisoners uncovered at the Abu Ghraib prison.

Bush has said he wants Rumsfeld to "stay in my Cabinet." But a chorus of criticism from Capitol Hill has at least one Republican wondering whether Rumsfeld, and perhaps Joint Chiefs of Staff Chairman Richard Myers, might have to step down.

"Let's get the facts before we indict Secretary Rumsfeld," Sen. Chuck Hagel, R-Neb., told CBS' "Face the Nation" on Sunday. "I think they have made major mistakes. And we will see how far this goes and where it goes."

But Hagel added: "Yes, I think it's still in question whether Secretary of Defense Rumsfeld and, quite frankly, Gen. Myers can command the respect and the trust and the confidence of the military and the American people to lead this country."

Hagel said abuses will have major repercussions abroad.

"This is deeper and wider than I think most in this administration understand," he said. "Aside from the fact we're losing the Iraqi people, we're losing the Muslim, Arab world, and we're losing the support of our allies."

Rumsfeld told Congress on Friday that more "sadistic" photos and video images were still to be released.

Sen. John Warner, R-Va., chairman of the Senate Armed Services Committee, said Pentagon investigators will give lawmakers the photos to view in private. Others urged the administration to make them public quickly.

"If there's more to come, let's get it out," Sen. Lindsey Graham, R-S.C., said on NBC's "Meet the Press." "For God's sake, let's talk about it because (U.S. military) men and women's lives are at stake given how we handle this."

Bush's trip across the Potomac River to the Pentagon comes a day after it was announced that Spc. Jeremy C. Sivits, 24, of Hyndman, Pa., will be the first soldier to face a court-martial in connection with the abuse. He will be tried May 19 in Baghdad on charges of mistreating detainees. In all, seven soldiers face abuse allegations.

A senior Pentagon official told The Associated Press on Sunday that guards and interrogators in Iraq were expected to follow the Geneva Conventions and other international rules against cruel, inhumane or degrading treatment of prisoners.

They were not to apply techniques approved in April 2003 for use at the Guantanamo Bay prison in Cuba where suspected al-Qaida terrorists are held, said the official, who spoke on condition of anonymity.

Yet to be determined is whether U.S. soldiers, including those facing courts-martial for abuses committed at the Abu Ghraib prison, were encouraged by commanders to use aggressive practices intended to elicit more information more quickly from prisoners.

Pentagon spokesman Bryan Whitman said the abuse of Iraqi prisoners were beyond the bounds of authorized practices.

"The policies of the United States and the Defense Department are consistent, in that we do not permit activities or interrogation procedures that are torturous or cruel and that all the techniques that are approved for use are within the law," Whitman said.

Some lawmakers say there are clear indications from the widely published photos of troops abusing Iraqi prisoners that even if such acts were not ordered or condoned by U.S. commanders, the soldiers thought they were at least condoned.

"All the guards are smiling, they're taking all these pictures, because they know that nobody above them is going to object. They have to know that somebody up there is agreeing to it," Sen. Patrick Leahy, D-Vt., said on ABC's "This Week."