In his weekly radio address on Saturday, Bush again suggested the abuse scandal was limited to those directly involved at Baghdad's Abu Ghraib prison.
He pointed out that charges have been filed against seven soldiers and the first trial was set to begin next week.
"My administration and our military are determined that such abuses never happen again," Bush said. "All Americans know that the actions of a few do not reflect the true character of the United States armed forces."
US military interrogation techniques have come under scrutiny after revelations of abuse at Abu Ghraib.
Prisoners were kept naked, stacked on top of each other, compelled to wear hoods over their heads, forced to engage in sex acts, struck by jailers, photographed in humiliating poses. In some cases, prisoners were apparently beaten severely and sexually assaulted.
Defence officials said on Friday the US military had prohibited several interrogation methods from being used in Iraq, including sleep and sensory deprivation and body "stress positions."
The abuse scandal, coupled with other bad news from Iraq, has been a factor in a drop in Bush's approval rating. A Newsweek poll released on Saturday indicated the president's approval rating sliding to 42%, a new low for his presidency.
Bush has stood by Defence Secretary Donald Rumsfeld amid calls by Democrats for him to resign over the abuse scandal.
But in a report that may further stoke the controversy, the New Yorker magazine said Rumsfeld approved a secret plan that brought unconventional, harsh interrogation methods to Iraq to gain intelligence about the growing insurgency.
The plan's rules were: "Grab whom you must. Do what you want," according to one former intelligence official cited by Hersh.
That ultimately led to the abuse of Iraqi prisoners, said the article, which was written by Pulitzer Prize-winning journalist Seymour Hersh, who exposed the 1968 My Lai massacre by US troops in Vietnam.
Bush said in his radio address the United States was working with Iraqi leaders on an interim government to take power on 30 June. US troops will stay in Iraq after that for security, he said.
Bush also noted the beheading of American civilian Nicholas Berg in Iraq.
"The savage execution of this innocent man reminds us of the true nature of our terrorist enemy, and of the stakes in this struggle," he said.