Iraqi security forces are preparing for a new offensive targeting what they refer to as "outlaws" in the southern city of Amarah.
Helicopters dropped leaflets across the city Saturday urging residents to stay home and not to interfere with the operation. A U.S. military official declined to provide details of the operation, but said it was being organized by Iraqi forces.
Amarah borders Iran to the south, and is believed to be a major region for weapons smuggling.
Influential Shi'ite cleric Moqtada al-Sadr has expressed support for the Iraqi-run operation. His Mahdi Army militia agreed to a cease-fire with the Iraqi government last month, but the cleric has vowed to continue resisting U.S.-led forces.
In northeastern Iraq Saturday, a female suicide bomber wounded at least 30 people in an attack at a cafe in Qara Tappah, where soccer fans were celebrating Iraq's victory in a World Cup qualifying match.
In a separate development, the U.S. military says coalition forces killed two suspected al-Qaida militants and detained 33 others in separate operations in central and northern Iraq.
In one incident, a military statement says militants with ties to an al-Qaida in Iraq bombing network opened fire on coalition troops south of Mosul. It says the troops responded, killing one armed militant and detaining nine others.
The military says coalition forces also discovered and destroyed a terrorist hideout in a town southwest of Mosul Saturday. It says the forces killed one suspected militant in a clash at the hideout.