Al-Maliki said he did not authorize the assault, and described it as "unjustified."
The U.S. military said the operation targeted a death squad.
The raid sparked a gun battle with militiamen loyal to the radical Shi'ite cleric Muqtada al-Sadr, whose group is part of al-Maliki's coalition. At least three civilians were killed in the battle.
(AFP, AP)