Members of Congress today expressed shock and disgust after viewing hundreds of photographs and video clips related to the abuse of U.S.-held prisoners in Iraq, material that they said would be withheld from the public to protect the integrity of military trials and to avoid further inflaming America's enemies.

"What we saw is appalling," said Sen. Bill Frist (R-Tenn.), the Senate majority leader, after the Defense Department brought a computer disc containing the digital photos and video clips to Capitol Hill and displayed them on a computer in a closed-door meeting.

Frist said the photos were "consistent" with those that have been publicized to date. He added, "They go beyond that in many ways in terms of the various activities that are depicted, some totally unrelated to the Abu Ghraib prison or to the prisoners there."

He said, "Many of these photographs . . . appeared to relate to the abuse of prisoners. And then there were many, many others that were unrelated, but very, very appalling to all of the senators who saw them." He provided no further explanation.

"We left with a feeling of disappointment that the behavior of a few has reflected in a way that unfortunately hurts the reputation of the thousands, tens of thousands, 130,000 or more armed services personnel over there fighting for us each and every day," Frist said.

Frist and Sen. John W. Warner (R-Va.), the chairman of the Senate Armed Services Committee, declined to specify what the photos and videos showed, noting that they are part of active investigations.

Warner, whose committee is looking into the prisoner abuse scandal, said the material would remain under the control of the Pentagon, which is taking disciplinary action against some of the military police personnel who allegedly participated in the abuses late last year at the Abu Ghraib prison west of Baghdad.

Keeping the pictures under wraps "protects the integrity of the legal process" and avoids "inspiring the enemy" to harm members of the U.S.-led coalition or civilians in Iraq, Warner said. Revenge for the prison abuse was cited as a motive by the killers of Nicholas Berg, an American civilian who was beheaded in Iraq in a videotape that was posted on an Islamic militant group's Web site yesterday.

Warner indicated that the photos are likely to become public at some point, since no one knows how many copies have been made or who has them. But he said they would not be released by the executive branch or by Congress.

Sen. Bill Nelson (D-Fla.) said, "What I have seen is disgusting and it is disappointing." He said there were "obvious examples in videos of inhumane treatment" and that, in one photo, he counted seven or eight troops in a hallway in which several Iraqi prisoners were tied together naked on the floor.

"Now, you can't tell me that all of this was going on with seven or eight Army privates," Nelson said. "And so the question is: How far up the chain of command did these orders [go], and where did that failure of the command and control occur? And we're going to get to the bottom of it."

Nelson said one poor-quality video appeared to show Iraqi prisoners about to be sodomized, although "it's not clear that the actual act of sodomy was being perpetrated on the videos that I've just seen."

He said he did not see any videos showing rape, either of a male or female prisoner. He said there were "attempted medical treatments in the prison" that he did not further describe. And he said he saw what appeared to be "some wounds from dogs."

"This is aberrant behavior, and we need to find out who the perpetrators were, where the command and control lapsed and bring these folks to justice," Nelson said.

In answer to a reporter's question, he said, "Some of the videos are more disturbing than the still photos that you've seen."

Sen. John Cornyn (R-Texas) said that in addition to photos that have already appeared in the press, "there were some other pictures . . . involving interaction between our own troops, but not involving any Iraqis."

Rep. Jane Harman (D-Calif.), the ranking Democrat on the House Intelligence Committee, said what most shocked her was a video clip of a handcuffed prisoner beating his head against a wall. She said another video showed a group of men masturbating.