Iranian Supreme Leader Ayatollah Ali Khameinei says he is ready to give his life in battle if his country is attacked.
The United States and Israel have refused to rule out air strikes to hinder what they see as Tehran's pursuit of atomic weapons.
The ayatollah, who has accused Washington of seeking any excuse to start a war, stressed he would remain in the public eye if war came, unlike US officials whom he accused of fleeing for cover after the September 11th attacks in 2001.
"If this nation is tested by a bitter experience, I will wear battle fatigues and will be ready to sacrifice myself at the head of the nation," he told pilgrims in the northeastern holy city of Mashhad today.
"After September 11, there was no news of US President (George W. Bush) and his deputies for two or three days. They went into hiding. I am not like that," he added in the speech broadcast on state television.
France, Britain and Germany have offered Iran economic incentives if it abandons work on its nuclear fuel cycle -
activities that could give Iran the ability to produce highly enriched uranium fuel or plutonium for bombs.
"It is a fiction that Iran is making an atom bomb, it is not true," the ayatollah said. "It is an excuse. If not this, Americans will find another excuse for conspiring against Iran, such as terrorism or human rights."
European and Iranian negotiators are scheduled to meet in Paris later this week to assess progress in talks, which remain deadlocked over Tehran's refusal to end uranium enrichment as demanded by the Europeans.