Sadr said in a statement read during Friday prayers in Sadr City that his threats to wage "open war" was meant "against the occupiers only," Voices of Iraq reported.

Located in eastern Baghdad, Sadr City experienced frequent skirmishes between what the U.S. considers Iranian-backed "special groups" loosely affiliated with Sadr's Mahdi Army and Iraqi government forces supported by the U.S. military. The violence corresponds to a decision by Iraqi Prime Minister Nouri al-Maliki to confront Shiite militias in Basra province.

"I give the Iraqi government the last warning that we would wage an open war until liberation if it failed to rein in the militias infiltrated into it," the statement said, referring to the military wing of the Supreme Islamic Iraqi Council, the Badr Organization.

The statement continued by saying his loyalists do not wish to reach an agreement on the status of U.S. forces in Iraq following the expiration of the U.N. mandate government military operations in Iraq.

"We would never accept it no matter how hard we have been fought or even killed," he said.

Emergency officials in Sadr City reported 11 killed and 74 wounded in overnight violence.