NBC News — Iran's supreme leaders warned of a tough response should Israel and the U.S. launch a military strike over the country's nuclear program. Ayatollah Ali Khamenei told officers at a military academy in Tehran those who attacked Iran should be ready to receive a "strong slap and an iron fist."

Khamenei made his comments two days after the U.N. Atomic Agency released a report that for the first time said Iran was suspected of conducting secret experiments to develop nuclear weapons. Iran's President slammed the report on wednesday. Iran maintains its nuclear program is intended for peaceful purposes.