Elsewhere, a string of car bombings and rocket salvos hit Baghdad as insurgents defied efforts by U.S. and Iraqi security forces to stabilize the capital.
Among attacks today, rockets and mortar bombs crashed into a market in a Shi'ite area in southern Baghdad. There are conflicting reports of casualties.
A car bomb also killed two people in central Baghdad, near the Iranian Embassy.
Meanwhile, radical Iraqi cleric Muqtada al-Sadr urged Iraqi security forces not to work with U.S. troops in enforcing a new Baghdad security plan.
Al-Sadr's location has been a mystery for several weeks. Iraqi and U.S. officials say he has gone to Iran, a claim denied by both Tehran and al-Sadr's movement.