Al-Sarkhi last Friday told supporters that Americans are responsible for what is happening in Iraq, according to his official website. He also blamed the bloodshed on the call by al-Sistani for volunteers to join Iraq's forces in the fight against the ISIS militants.

In 2006, the cleric's supporters attacked the Iranian Consulate in Basra, about 300 miles (500 kilometers) south of Baghdad.

Protesters were incensed about insulting remarks made about the cleric on an Iranian TV program. They threw stones and set fire to a building at the consulate.