WASHINGTON —  Secretary of State Colin Powell (search) cautioned Sen. Edward M. Kennedy (search) to be more careful in criticizing the war in Iraq after the Massachusetts Democrat called the conflict "George Bush's Vietnam."

Kennedy "should be a little more restrained and careful in his comments because we are at war," Powell said Tuesday on Fox News Radio's "Tony Snow Show."

Powell said debating the Iraq war was appropriate and an important part of American democracy. But, he said, "this is the also the time that we rally the nation behind the challenge that we face in Iraq and Afghanistan."

Powell acknowledged that he did not see Kennedy's speech because he was in Haiti, where he met with the country's interim government.

Kennedy said Bush misled the public about the war, the economy and education, compromising America's reputation at home and abroad.

"In this administration, truth is the first casualty of policy," said Kennedy, a prominent supporter of fellow Massachusetts Sen. John Kerry's (search) bid for the White House.

Kennedy spokesman David Smith said the senator "has an enormous amount of respect for Secretary of State Colin Powell and he understands why the secretary feels the need to defend the president's policies."