Tehran: A military strike against Iran could turn the Middle East into a "ball of fire" and push Iran to a more aggressive stance on its nuclear program, the head of the UN nuclear watchdog said.

"In my opinion, a military strike will be the worst...it will turn the Middle East to a ball of fire," International Atomic Energy Agency chief Mohamad Al Baradei told Al Arabiya television.

It also could prompt Iran to press even harder to seek a nuclear program, and force him to resign, he said.

Iran also called Israel a "dangerous regime" on Saturday, after a US report that the Jewish state had carried out a large military rehearsal for a potential bombing of Iran’s nuclear facilities.

"It demonstrates the Islamic Republic of Iran's view that this [Israel] is a dangerous regime and an impediment to peace and calm in the region and world," Iranian government spokesman Gholamhossein Elham said.

Western powers suspect Iran is seeking to develop nuclear bombs. Israel has described Iran's nuclear programme as a threat to its existence.

Earlier this month, Israeli Transport Minister Shaul Mofaz told an Israeli newspaper an attack on Iran looked "unavoidable" if it continues its nuclear programme.