Iran's Supreme leader Ayatollah Ali Khamenei said on Monday that Iran is set to deliver a "punch" that will stun world powers during this week's 31st anniversary of the Islamic revolution, AFP reported.

The country's top cleric was marking the occasion when Iran's air force gave its support to revolutionary leader Ayatollah Ruhollah Khomeini, a key event which led to the toppling of the U.S.-backed shah on February 11, 1979.

This year's anniversary is expected to become a flashpoint between security forces and supporters of opposition leaders Mir Hossein Mousavi and Mehdi Karroubi, who charge that the June re-election of President Mahmoud Ahmadinejad was rigged.