"If the United Nations won't act, if Saddam Hussein will not act, if he continues to defy the world, the United States in the name of peace will lead a coalition to disarm Saddam Hussein," Bush said to a standing ovation from Republican faithful at a political rally at Phoenix's Dodge Theater.

White House spokesman Ari Fleischer, who said on Saturday it would not be hard at all to form a coalition against Iraq, told reporters on Bush's plane on Sunday that the U.N. negotiators are facing a key week.

"We will see what happens in New York. This is the United Nations' chance to do some good or this is the United Nations' chance to fail," Fleischer said.

» Bush Urges U.N. Act on Iraq for Sake of Peace