US President George W. Bush has told Americans the threat of a deadly attack by Iraq on the United States is growing.
But in the speech in Cincinnati, Mr Bush insisted military action is not imminent and pledged to build an international coalition against Saddam Hussein if he defies demands to disarm.
"If we have to act, we will take every precaution that is possible. We will plan carefully. We will act with the full power of the United States military. We will act with allies at our side. And we will prevail," Mr Bush said.
Mr Bush said Iraq's history and technological capabilities make it a "unique" threat, and that lawmakers' willingness to give him authority to use force would "tell the United Nations, and all nations, that America . . . is determined to make the demands of the civilised world mean something.
He said Iraq has ballistic missiles with a likely range of hundreds of miles, far enough to strike Saudi Arabia, Israel, Turkey and other nations.
Iraq said it is incapable of producing nuclear, chemical, or biological weapons after seven years of UN inspections in the 1990s. It rejected as "lies, and fabrications" a report from Prime Minister Mr Tony Blair that Saddam could deploy chemical or biological weapons within 45 minutes.