TEHRAN: Iran will "annihilate" the Israeli cities of Tel Aviv and Haifa if it comes under attack by the Jewish state, supreme leader Ayatollah Ali Khamenei warned on Thursday.

"Every now and then the leaders of the Zionist regime threaten Iran with a military attack," Khamenei said in a live televised speech from the northeastern holy city of Mashhad, referring to Israel.

"They should know that if they commit such a blunder, the Islamic republic will annihilate Tel Aviv and Haifa," he said.

Iran is said to possess ballistic missiles capable of reaching Israel. It also has close relations with Israel's foes in the region, including Lebanon's Hezbollah and Palestinian militants in the Islamist-ruled Gaza Strip.

Khamenei spoke with little sign of an easing in Tehran's position in its confrontation with the West over its disputed nuclear programme of uranium enrichment.

Israel, widely believed to be the Middle East's sole but undeclared nuclear power, suspects that Tehran is seeking atomic arms, a fear shared by the United States and Western powers, and has not ruled out a military strike.

Washington has also refused to rule out the military option, but insists it prefers a diplomatic solution to the nuclear stand-off.

US President Barack Obama in Israel on Wednesday accepted that the Jewish state would not cede its right to confront Iran's nuclear threat to the United States.