The late-night cries of "Allahu Akbar!" and "Death to the Dictator!" throughout Tehran Friday are a direct challenge to the cleric who has ultimate authority under Iran's constitution. They come hours after Supreme Leader Ayatollah Ali Khamenei warned opposition supporters to stop protesting the June 12 election they say was rigged in favor of hardline President Mahmoud Ahmadinejad.
Opposition leader Mir Hossein Mousavi borrowed the tactic from the 1979 Islamic Revolution led by Ayatollah Ruhollah Khomeini, who asked Iranians to show unity against the U.S.-backed shah by shouting "Allahu Akbar" from their roofs.