"I shared a deep disgust that those prisoners were treated the way they were treated," Bush told reporters.
Bush's comments came as the British army said it was investigating separate allegations that its soldiers abused an Iraqi prisoner, and as the United Nations and several human rights groups denounced the alleged offenses by U.S. troops.
The images of Westerners callously humiliating Iraqis at the Abu Ghraib prison near Baghdad could inflame anti-American sentiment in the Arab world at a delicate time. U.S. officials say they fear the revelations will set back their efforts to win the trust of Iraqis before the Bush administration's June 30 deadline for handing over sovereignty to Iraqis.
The site of the alleged abuses also represents an unfortunate symbol for U.S. troops, who are eager to be seen as liberators. The Abu Ghraib prison was infamous during Saddam Hussein's rule as a den of torture.
Kofi Annan, the U.N. secretary-general, said he was "deeply disturbed" by photographs of smiling U.S. troops standing over naked Iraqi prisoners and subjecting them to humiliation.
Eight others in the unit face less severe administrative charges. In addition, another member, Pvt. Lynndie R. England, has been reassigned to Fort Bragg in North Carolina, where she is being detained, her family says. It is not clear whether she will face charges. England and Graner are engaged, her parents said.
A total of 17 people were suspended from their posts at the prison after a military investigation. Army Reserve Brig. Gen. Janis L. Karpinski, the highest-ranking officer to be suspended, faces administrative charges. One of those dismissed was a private contractor working as an interpreter.
An account sent to relatives by one of the soldiers charged describes a range of abuses inside the prison. Sergeant Frederick describes how detainees were left in isolation cells for days without clothes - or sometimes in women's underwear - with no light, ventilation, water or toilet.
The 1949 Geneva Conventions prohibit "outrages upon the personal dignity, in particular humiliating and degrading treatment" of detainees.
Frederick's notes indicate that Army intelligence and criminal investigators witnessed and even encouraged the abuse. Human rights groups said the role of higher-ranking soldiers should be investigated. Some expressed concern that private contractors, operating in Iraq "with virtual impunity," might be violating international law.
"Allowing private contractors to operate in a legal vacuum is an invitation to abuse," said Kenneth Roth, executive director of Human Rights Watch.