Thousands of followers of Lebanon's powerful Hezbollah militant group are rallying against an anti-Islam film that has provoked a week of unrest in Muslim countries worldwide.

The leader of the Shiite group, Hassan Nasrallah, called for Monday's protests. He says the U.S. must be held accountable for the film because it was produced in America.

Protesters including white-turbaned Muslim clerics and thousands of other men and women are massing in Hezbollah strongholds south of Beirut.

Most of the men tied headbands around their foreheads in green and yellow _ the colors of Hezbollah _ with the words "at your service God's prophet" written on them.

Many Muslims are angry because the film denigrates Islam's Prophet Muhammad.