Clashes in Baghdad Slum Kill 22 Iraqis, U.S. Soldier  BAGHDAD (Reuters) - Iraqi fighters battled U.S. troops in a  Baghdad slum district Tuesday, raising the death toll to 22  Iraqis and one U.S. soldier and threatening to wreck a  cease-fire called by rebel Shi'ite cleric Moqtada al-Sadr.