Anti-U.S. Shiite cleric Muqtada al-Sadr is calling on followers to hold weekly protests against a long-term security deal that the Iraqi government and U.S. are negotiating.

The security agreement aims at setting the terms for a long-term, reduced U.S. military presence in Iraq after the bulk of American forces withdraw. Al-Sadr sharply opposes the U.S. presence and his Mahdi Army militia has frequently attacked U.S. troops.

A statement from al-Sadr says Iraqis should hold demonstrations every week after Friday prayers in every part of the country "until further notice or until the agreement is canceled."

The statement Tuesday also demands that any agreement reached with the Americans be put to a popular referendum.