"The U.S. military drive to train and equip Iraq's security forces has unwittingly strengthened anti-American Shiite Muslim cleric Muqtada al-Sadr's Mahdi Army militia, which has been battling to take over much of the capital city as American forces are trying to secure it. U.S. Army commanders and enlisted men who are patrolling east Baghdad, which is home to more than half the city's population and the front line of al-Sadr's campaign to drive rival Sunni Muslims from their homes and neighborhoods, said al-Sadr's militias had heavily infiltrated the Iraqi police and army units that they've trained and armed."