By Ibon Villelabeitia BAGHDAD, March 1 (Reuters) - U.S. and Iraqi troops will soon launch a major sweep in the Shi'ite militia bastion of Sadr City, military officials said on Thursday, a pivotal moment for the make-or-break security crackdown in Baghdad. American-led forces have conducted targeted raids in the Mehdi Army militia stronghold of anti-American cleric Moqtada al-Sadr aimed at death squad leaders, but have so far held off from a concerted push into the teeming slum. In the new campaign, U.S. and Iraqi troops will set up joint checkpoints in Sadr City and conduct large-scale door-to-door operations on houses and buildings, a significant escalation in a plan regarded as the last chance to avert sectarian civil war. Washington calls the Mehdi Army the greatest threat to peace in Iraq. Sadr is a key political ally of Shi'ite Prime Minister Nuri al-Maliki and the raids could test Maliki's pledge to target all militants regardless of sectarian affiliation. Details of the plan emerged during a meeting of senior U.S. and Iraqi military commanders on Thursday in Sadr City, which was also attended by the mayor of Sadr City. Sipping minted tea in a police station as four helicopter gunships hovered overheard, they agreed to set up a joint security station in Sadr City in a few days. It will be the first U.S. forces have had a permanent presence in the slum since the 2003 invasion. "We have conducted special operations in Sadr City for some months but this will be the first time we will launch full-scale operations there and the first time we will have a permanent presence there," said Colonel Billy Don Farris, coalition forces commander for Sadr City and Adhamiya neighbourhoods. "There will be no sanctuaries in Iraq. We are going to go to every building and every house and incrementally clear the area. We will target any group that attacks Iraqi and U.S. troops," he told Reuters. U.S. commanders have said past plans to stabilise Baghdad failed because the Shi'ite-led government shied away from cracking down on Shi'ite militiamen. These are blamed for many sectarian killings but regarded by many Shi'ites as their best defence against Sunni Arab insurgents such as al Qaeda. ELUSIVE ENEMY Sadr, who led two uprisings against U.S. forces in 2004, criticised the new security plan this week and said it would not work because U.S. forces were involved. Sheikh Raheem al-Darruji, the mayor of Sadr City, said the Sadrists were willing to give the plan a chance but said if attacks against the Shi'ite community continued "the people of Sadr City would defend again their neighbourhoods". "We think weapons should be in the hands of the Iraqi forces, but people have to be protected from the terrorists." He protested about American "heavy tactics" in recent raids. U.S. and Iraqi forces have deployed 90,000 troops and police in Baghdad. Around 15 joint security stations have been opened, where American soldiers live with their Iraqi counterparts in an effort aimed at holding cleared areas. In Sadr City, home to two million impoverished Shi'ites, U.S. forces will face an elusive enemy. Mehdi Army commanders have fled and the black-clad militiamen are keeping a low profile, avoiding a confrontation with U.S. troops. Portraits of the scowling Sadr stare down from many billboards. Sadr's network of social and religious services has deepened a sense of Shi'ite militancy, making the eastern Baghdad enclave almost impenetrable for outsiders. Barefoot children play by pools of raw sewage and goats are herded amid mounds of rubbish,although projects funnelled by the Shi'ite majority in power appear to be bearing some fruit. The sectarian loyalties of Iraq's security forces, whose police is heavily Shi'ite, have cast doubt that Maliki will crush Shi'ite militants with the same determination as he is pursuing Sunni Arab insurgents. This time things will be different, said Major-General Kareem Abdul-Rahman, Iraqi commander for eastern Baghdad. "I have but one order from Maliki: to enforce the law," he said.
