Officials from the party of radical Shi'ite cleric Muqtada al-Sadr, which is linked to the militia, the Imam Al-Mahdi Army, denied any of its fighters were killed.
The United States is leaning on Iraq's government to rein in militias, which are responsible for much of the country's sectarian violence. Many of the militias are supported by political parties.
Meanwhile, in the northern city of Kirkuk, a 36-hour curfew was lifted after Iraqi and U.S. troops carried out a massive security operation aimed at hunting down insurgents. Police said they detained 180 people and seized arms and ammunition.
Oil-rich Kirkuk is the center of a power struggle between Sunni Arabs, ethnic Turkish Turkomans, and Kurds.
In other news, a police official said today that an entire 1,200-strong unit fell sick and three officers died after eating a suspect meal.
Colonel Badr al-Ziadi said his men started falling ill immediately after breaking their daylight Ramadan fast on October 8 at the Numaniyah training base in eastern Iraq, and that 60 of them had required hospital treatment.
"We are not sure whether there was something in the water or if the food was spoiled," he said.
Also, the Iraqi Interior Ministry says that unidentified gunmen assassinated Lieutenant General Amir al-Hashimi, the brother of Sunni Vice President Tariq al-Hashimi, in Baghdad today.
(AP, BBC, AFP)