Scores of lawmakers yesterday viewed unreleased photos and videos of Iraqi detainees being sexually humiliated and physically threatened. The images, which included Iraqi corpses, U.S. troops having sex with each other, and previously undisclosed videos of at least one inmate ramming his head into a wall, convinced some legislators that the number of Americans who violated military protocol is larger than previously thought.

The private screenings arranged by the Pentagon -- one for senators, one for House members -- surely ranked among Congress's more bizarre scenes. House members silently crammed into a standing-room-only committee room as hundreds of images, some described as pornographic, flashed on a screen for a few seconds each. Lawmakers emerging from that session, and from a less-crowded Senate room, seemed almost at a loss for words.

"What we saw is appalling," said Senate Majority Leader Bill Frist (R-Tenn.). "I saw cruel, sadistic torture," said Rep. Jane Harman (D-Calif.). Sen. Richard J. Durbin (D-Ill.) told Reuters: "There were some awful scenes. It felt like you were descending into one of the rings of hell, and sadly it was our own creation."

Several lawmakers said the images differed more in quantity than in essence from photos beamed worldwide in recent days, and they questioned whether yesterday's revelations would substantially change the debate over U.S. treatment of Iraqi detainees in the Abu Ghraib prison and elsewhere. "It is consistent with the photos that you've seen in the press to date," Frist said. He said the images should not be released by the Pentagon, but other lawmakers said they should, on the assumption they will leak out.

Although it often was difficult to determine what was happening in the photos and videos, some legislators said the pictures suggest that abuses were committed by more than the half-dozen low-ranking military personnel directly implicated thus far. "It's not just seven reservists" shown forcing detainees into sexually humiliating poses or threatening them with snarling dogs, said Rep. Sherwood L. Boehlert (R-N.Y.). "I think it goes beyond that."

Sen. Bill Nelson (D-Fla.) had a similar reaction. He said one photo, which showed "troops that are in a hallway [in Abu Ghraib], where you've seen the clump of people tied together on the floor, we counted seven or eight troops. . . . Now, you can't tell me that all of this was going on with seven or eight Army privates. And so the question is: How far up the chain of command did these orders [go]?"

Nelson said his assertion was not a certainty but "a conclusion."

"This time I saw the photo more elongated and saw several other troops' legs and boots before the photo cut off," he said. "Where you have that many people participating with the obvious activity of prisoners clumped up and tied up on the floor naked, then obviously other people, is my conclusion, are going to know about that kind of activity."

Asked of reports that a video showed an inmate being sodomized with a broomstick, Nelson said, "You could not say that there was actually the act of sodomy, but it appears that that may be the preparation for it." Nelson and other lawmakers said they saw no evidence of rape or any sexual activity between an American and an Iraqi, although several people reported images of troops having sex with each other.

"It certainly was so far unbecoming of what we expect from American soldiers," Sen. Norm Coleman (R-Minn.) said.

Rep. David E. Price (D-N.C.) said there were images of male Iraqi detainees masturbating, apparently at the orders of U.S. guards. Another video, he said, showed inmates "butting their heads into a wall, very hard. It's hard to tell what's going on." A House member "shouted out, 'What is this all about?' " but Price said Pentagon officials showing the videos had no answer.

Harman speculated that the man was "probably trying to knock himself unconscious and avoid having to live through the experience."

Rep. George Miller (D-Calif.) disagreed, saying U.S. troops almost certainly forced the detainee to bang his head against the wall, because they were there to videotape it. Miller called the photos and videos "very disturbing. And it's very clear why the Iraqi people and others would be so insulted and upset by their treatment."

Majority Leader Bill Frist, left, and Armed Services Committee Chairman John W. Warner after a private Senate screening.Sen. Bill Nelson (D-Fla.) reacted to the Abu Ghraib photo of "the clump of people tied together on the floor" by saying, "And so the question is: How far up the chain of command did these orders [go]?"Sens. John Cornyn and Kay Bailey Hutchison, both Texas Republicans, are interviewed after Pentagon's private screening of unreleased prison abuse images.