President Bush is urging the Pentagon to take action against any U.S. soldier who has abused Iraqi prisoners.
Iraq was a major theme when the president left Washington for his first major campaign trip of the election year.
In a speech in a small town in Michigan, Mr. Bush defended his decision to invade Iraq, saying Iraqi leader Saddam Hussein defied the world. He said the coalition will prevail, and sovereignty will pass back to Iraqi hands on schedule. "There are a lot of people there wondering if America will keep its word. They wonder whether or not politics will cause politicians to change their mind in the midst of this transfer of sovereignty. I am not changing my mind," he said.
The president said coalition troops removed a regime of hatred and violence. He outlined the abuses of Saddam Hussein's regime, including torture and rape. "The world is better off without Saddam Hussein in power. The world is better off because he sits in a prison cell. Because we acted, torture rooms are closed, rape rooms no longer exist, mass graves are no longer a possibility in Iraq," he said.
Mr. Bush made no direct mention of the controversy surrounding the treatment of some prisoners by U.S. forces at a detention facility near Baghdad. But top aides to the president left no doubt the troubling evidence of abuse is very much on his mind.
White House spokesman Scott McClellan told reporters that before leaving Washington, Mr. Bush called Secretary of Defense Donald Rumsfeld to check on the status of the investigation.
Mr. McClellan said the president urged his defense secretary to make sure any soldier who abuses prisoners is punished. The spokesman said Mr. Bush made clear appropriate action must be taken against those responsible for "these shameful and appalling acts."
Mr. McClellan stressed they are the actions of a few and do not represent the 99 percent of U.S. forces in Iraq who, he said, are doing a superb job.
He also contrasted the American soldiers under investigation to those who committed wrongdoings under the former Iraqi regime. He said Saddam Hussein encouraged and tolerated this kind of behavior, the United States does not.