Committee Chairman John Warner, R-Va., said senators are close to negotiating an agreement with the Pentagon to view possibly more damaging photos and some videos of abuse that have been uncovered as part of the military investigation. It was unclear whether the pictures would be released to the public, but Defense Secretary Donald Rumsfeld warned last week that the content is so outrageous the photos are "hard to believe."

Vice President Richard Cheney said Tuesday that the release of the photos must be handled in a responsible fashion.

"We wouldn't want — as a result of the release of pictures and the mistreatment of that kind of information — to allow guilty parties off the hook, so that they couldn't be prosecuted," he said in a radio interview. "By the same token, you don't want to see innocent people inappropriately maligned by virtue of the release of photographs."

Asked to describe the unpublished photos, Cheney said, "It was very strong stuff, and I'll just leave it at that."

At the Senate hearing, partisan politics emerged, with Democrats grilling military leaders and some Republicans downplaying the scandal and expressing anger at media and international attention.

"I am also outraged that we have so many humanitarian do-gooders right now crawling all over these prisons, looking for human-rights violations while our troops, our heroes, are fighting and dying," said Sen. James Inhofe, R-Okla.

Fellow Republican John McCain of Arizona, who sits next to Inhofe on the dais, appeared to take issue with Inhofe's comments.

In discussing the benefits of the regulations governing international conduct during war, McCain echoed the phrase "humanitarian do-gooders" and expressed his support for the Geneva Conventions.

"It seems to me . . . that we distinguish ourselves from our enemies by our treatment of our enemies," said McCain, who was brutalized as a prisoner of war during Vietnam.

Sen. Carl Levin, D-Mich., meanwhile, disputed the Pentagon's claim that the prison abuse was the work of a handful of people.

"The despicable actions . . . not only reek of abuse, they reek of an organized effort and methodical preparation for interrogation," he said. "The collars used on prisoners, the dogs and the cameras did not suddenly appear out of thin air."

Sen. Susan Collins, R-Maine, said she found it difficult to believe that a rogue group of prison guards would have, on their own, chosen bizarre sexual humiliations designed to particularly humiliate Muslim men.