The U.S. military says 20 Sh'ite militia were killed in overnight clashes between U.S.-backed Iraqi forces and the Mehdi Army in Sadr City, the militia's Baghdad stronghold. Fighting in the Sadr City slum has claimed hundreds of lives since last month when U.S.-backed Iraqi forces launched a crackdown against Shi'ite militia groups in Baghdad and Basra. In a statement on Saturday, Moqtatda al-Sadr said he was giving the Shi'ite-led Iraqi government a 'last warning' to 'take the path of peace.'