"The possibility of this is very weak and it's more a matter of psychological warfare," the semi-official Mehr news agency quoted Larijani as saying.

"However, Iran is always ready to confront threats."

Earlier this month, US President George W. Bush ordered a second US aircraft carrier battle group to the Gulf and announced the deployment of Patriot anti-missile missiles to the region.

Washington was the most outspoken champion on the Security Council of its adoption of the first ever UN sanctions against Iran over its refusal to heed calls for a suspension of its uranium enrichment programme.

Iran insists that its nuclear activities are aimed solely at producing power for civilian needs, but the United States backs its Israeli ally in accusing the Islamic republic of covertly seeking to develop an atomic bomb.

Defence Minister Mostafa Mohammad Najjar issued a similar message of defiance, vowing that Iran would repulse any strike, of whatever size.

"The Islamic republic's armed forces are in a state of complete readiness and are monitoring everything in order to give a crushing response to even the smallest aggression or threat," the ISNA news agency quoted him as saying.

"I advise Mr Bush and his advisors to be rational and think about their own nation's interest."

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