Iran's supreme leader, Ayatollah Ali Khamenei, warned on Tuesday, March 20 his country would hit back at any attack by the United States or Israel, firming tensions in the showdown over Tehran's nuclear programme, AFP reported.

"We have said that we do not have atomic weapons and we will not build any. But if there is any attack by the enemies, whether it be United States or the Zionist regime, we will attack them at the same level as they attack us," he said in live televised speech to mark the start of the Iranian new year.

The comments reinforced Iran's position as it faces off against the West over its nuclear activities, and as it confronts Israeli and US threats of possible military action.

Khamenei, who was speaking in the western city of Mashhad, said Iran had a divine right to retaliate if struck.

"The Koran states that if an enemy attacks you first, the enemy will certainly be defeated," he said.

"This is God's law. We are not thinking of attacks and aggression, but we are attached to the existence and identity of the Islamic republic."