BAGHDAD, Oct 27 (Reuters) - U.S. forces moved into part of Baghdad's sprawling slum district of Sadr City on Friday, hunting for a U.S. soldier of Iraqi descent who was kidnapped on Monday, a U.S. military spokesman said. Witnesses and an official of the Mehdi Army, a militia loyal to Shi'ite cleric Moqtada al-Sadr, said there was a strong U.S. troop presence backed by air support in the northeast part of Sadr City. The official said the U.S. troops had not taken any aggressive action. U.S. troops rarely venture into the area, a stronghold of the Mehdi Army militia that Washington wants the government to disarm amid accusations it operates sectarian death squads. Asked about the U.S. activity in Sadr City, U.S. Lieutenant Colonel Christopher Garver said: "It's ongoing operations specifically related to the search for the missing soldier." U.S. forces were in the area where the soldier was thought to be, he said. The move into Sadr City came a day after the prime minister said Iraq's most notorious death squad leader escaped a major U.S.-led raid in Sadr City. Wednesday's ground and air assault targeted Abu Deraa, a feared warlord held responsible for a rash of brutal sectarian killings and kidnappings of Iraqi Sunnis. The operation, carried out by Iraqi special forces with U.S. advisers and air support, killed 10 "enemy fighters", according to a U.S. military statement. The U.S. military said during Wednesday's raid Iraqi forces also searched a mosque in connection with the hunt for the missing U.S. soldier, who left the safety of the fortified "Green Zone" on Monday to visit a relative. The raid caused tensions with Iraqi Prime Minister Nuri al-Maliki, whose government relies on Sadr's support. Maliki said he was not informed in advance of the full scope of the mission. U.S. forces have been out in force in various districts of the capital since Monday, conducting house-to-house searches and setting up checkpoints. They have been on the outskirts of Sadr City for several days, though U.S. Major General William Caldwell declined to say on Thursday which group was thought responsible for the kidnapping of the soldier, a linguist of Iraqi descent. (Reporting by Mariam Karouny and Claudia Parsons)
