WASHINGTON (CNN) -- Former President Jimmy Carter sharply criticized President Bush's handling of the war in Iraq Tuesday and told CNN he believes the U.S. invasion of the country may prove to be as big a blunder as the U.S.'s eight year involvement in the Vietnam War.

"It's going to prove, I believe, to be one of the greatest blunders that American presidents have ever made," Carter told Wolf Blitzer on 'The Situation Room.'

When asked how Iraq will be compared to Vietnam, Carter said it will be a "close call" but noted U.S. actions in Iraq are more publicized around the world than they were in Vietnam.

"I think its going to be a close call, but perhaps much more vividly known by the rest of the world than Vietnam was," Carter said.

But the former president said he disagreed with those who have labeled the situation in Iraq a "civil war."

"I think civil war is a serious -- a more serious circumstance than exists in Iraq," Carter said. "And I say that based on some of the civil wars with which we've been involved in the last few years."