DUBAI (Reuters) - Iran's most powerful authority said the Islamic Republic would destroy the Israeli cities of Tel Aviv and Haifa if Israel launched a military attack against it.

"At times the officials of the Zionist regime (Israel) threaten to launch a military invasion but they themselves know that if they make the slightest mistake the Islamic Republic will raze Tel Aviv and Haifa to the ground," Ayatollah Ali Khamenei said during an address, broadcast live on state television.

Israel has threatened military action against Iran unless it abandons nuclear activities which the West suspects are intended to develop nuclear weapons, allegations Tehran denies.

(Reporting By Marcus George; Editing by Janet Lawrence)