The disclosures made clear that suspected abuses by U.S. soldiers go well beyond those documented at the Abu Ghraib prison near Baghdad involving soldiers of a Maryland-based Army Reserve unit.
Defense Secretary Donald H. Rumsfeld condemned the abuses as "deeply disturbing" and "un-American." He vowed that appropriate action would be taken.
"The actions by U.S. military personnel in those photos," Rumsfeld said, "do not in any way represent the values of our country or of the armed forces."
Members of Congress, shocked and angered by the allegations, set the stage for their own inquiry, calling for public testimony from Rumsfeld and top civilian Pentagon leaders.
Senior lawmakers expressed concern that the images of extreme humiliation could severely damage U.S. security and relations with the rest of the world, especially Arab nations.
Several demanded that Congress open a broad investigation into all U.S. detention facilities, to try to determine whether systemic problems led to widespread abuse of detainees.
Sen. John W. Warner, the Virginia Republican who is chairman of the Armed Services Committee, promised a "public hearing at the first opportunity we can" with Rumsfeld and other senior officials. Warner, a former Navy secretary, said he was determined to examine what he called "one of the most extraordinary chapters that I have thus far witnessed" in more than half a century of association with the U.S. military.
Emerging from classified briefings with Army officials, senators criticized military leaders for failing to tell Congress earlier about the allegations against U.S. soldiers at the Abu Ghraib prison.
The case has sparked five military inquiries and led to criminal charges against six soldiers from a Maryland-based military police unit, as well as career-ending reprimands for six of their superiors.
Graphic photos from the Abu Ghraib prison, now shown around the world, depict naked captives being subjected to sexual humiliations and other abuses. Some soldiers from the 372nd Military Police Company, based near Cumberland, are shown smiling and giving thumbs-up signs.
Bush's spokesman said the president was not shown the photos of the abused prisoners until after they were disclosed in news reports. Nor did Bush learn of a scathing classified Army report about the Abu Ghraib abuses, which was completed in February, until news organizations reported on it this week, the spokesman said.
Tom Daschle, the Democratic leader in the Senate, demanded to know why Bush had not been told earlier about the report.
"Why, in other words, has there been this extraordinary disconnect, this unbelievable failure of communication, of oversight?" Daschle said.
Army officials said they were doing all they could to handle the widening allegations of abuse.
"We take maltreatment of detainees very seriously," said Gen. George Casey, vice chief of staff of the Army, after disclosing the additional investigations. "We are completely committed to getting to the bottom of this and holding accountable those who we find guilty."
Lawmakers pressed Casey and other Army officials in the secret briefings about the training of soldiers at the prison and the role of civilian contractors, as well as flaws in the chain of command that might have contributed to the scandal.
"This is as serious a problem of a breakdown in discipline as I've ever observed," Warner said.