Washington ? The abuse of Iraqi prisoners by U.S. troops went beyond the photos seen by most Americans, shaken lawmakers said Wednesday after viewing fresh pictures and video that they said depicted forced sex, brutality and dogs snarling at cowed prisoners.

Some members of Congress said they feared that making the images public would inflame international outrage and endanger Americans still in Iraq. The private screening of more than 1,600 photos in a top-secret room of the U.S. Capitol came the same day Defense Secretary Donald Rumsfeld defended some military interrogation techniques.

“I don’t know how the hell these people got into our Army,” said Colorado Republican Sen. Ben Nighthorse Campbell after viewing what he called a fraction of the images.

“I saw cruel, sadistic torture,” said Rep. Jane Harman, D-Calif., who said some of the images were of male prisoners masturbating. She said she saw a man hitting himself against a wall as though to knock himself unconscious.

Others said they saw images of corpses, military dogs snarling at cowering prisoners, women commanded to expose their breasts and sex acts, including forced homosexual sex.

“There were people who were forced to have sex with each other,” said Rep. Gary Ackerman, D-N.Y.

Rep. Trent Franks, R-Ariz., said, “There were some pictures where it looked like a prisoner was sodomizing himself” with an object. He said blood was visible in the photograph.

Not everyone reacted the same way to the additional photos.

House Majority Leader Tom DeLay, R-Texas, said he thought “some people are overreacting.”

“The people who are against the war are using this to their political ends,” he said.

The private screening marked the latest turn in a scandal that has prompted President Bush to apologize to the victims and Democrats to demand the dismissal of Rumsfeld.

Shortly before the viewing began, Rumsfeld defended military interrogation techniques in Iraq, rejecting contentions that they violate international rules and may endanger Americans taken prisoner.

Rumsfeld told a Senate committee that Pentagon lawyers had approved methods such as sleep deprivation and dietary changes as well as rules permitting prisoners to be made to assume stressful positions.

Gen. Richard Myers, chairman of the Joint Chiefs of Staff, also noted that the rules require prisoners to be treated humanely at all times.

But Sen. Richard Durbin, D-Ill., said some of the approved techniques “go far beyond the Geneva Convention,” a reference to international rules governing the treatment of prisoners of war.

Durbin noted that one American GI was missing in Iraq, his whereabouts unknown. Given the circumstances, he asked Rumsfeld, “wouldn’t it help if there was clarity from you and from this administration that we would abide by the Geneva Convention when it comes to civilian and military detainees unequivocally?”

Rumsfeld replied that the Geneva Conventions apply to all prisoners held in Iraq, but not to those held in Guantanamo Bay, where detainees captured in the global war on terror are held.

Any al-Qaida or Taliban personnel taken prisoner are to be treated consistent with the Geneva Conventions, under a decision made by Bush, Rumsfeld added.

He said the distinction was that the international rules govern wars between countries but not those involving groups such as al-Qaida. “Terrorists don’t comply with the laws of war. They go around killing innocent civilians,” Rumsfeld added.

The Defense Department is conducting multiple investigations into prisoner abuse.

Lawmakers were given three hours to see the photos and videos in top-secret rooms at the Capitol. The photos remained in the custody of the Pentagon as the administration tried to decide whether to release them to the public.