By Mariam Karouny BAGHDAD, Feb 9 (Reuters) - The arrest of an Iraqi official loyal to cleric Moqtada al-Sadr is the latest sign of growing U.S. pressure on the firebrand's movement, but it is unlikely to tempt his militia into an all-out fight with American troops. Shi'ite officials on Friday predicted the arrest of deputy health minister Hakim Zamili on Thursday would not be the last in what the Sadrists called American "provocation" as a major security crackdown gathers pace in Baghdad. But the Sadrist movement, more pragmatic than in 2004 when its Mehdi Army launched two uprisings against Americans forces that killed hundreds of people, said it would not be drawn into a confrontation with U.S. troops. Some Shi'ite officials outside the movement said it had too much to lose because of the political inroads it had made. "We will never react negatively to these provocations. To create chaos is the occupation's interest, while we want security for Iraq," Nassar al-Rubaei, head of the Sadrist bloc in parliament, told Reuters. "The more pressure the Sadrists come under, the stronger we will become." The U.S. military, without naming Zamili, on Thursday said a senior Health Ministry official had been detained on suspicion of infiltrating members of the Mehdi militia into the ministry and using it as a cover for sectarian killings. Washington has identified the Mehdi Army as the biggest threat to Iraqi security and U.S. forces have killed or detained hundreds of people from Sadr's movement in recent months. U.S. forces arrested Sadr's spokesman in Baghdad in January. The pressure on Sadr poses a dilemma for Shi'ite Prime Minister Nuri al-Maliki, who needs the youthful cleric's public support. But Maliki has also insisted the Baghdad security plan, which he announced last month, would target any militant regardless of sect. Sunnis accuse Shi'ite militias of widespread death squad killings in Baghdad, while Sunni insurgents often carry out major suicide bombings. Iraqi and U.S. forces have slowly begun the offensive, seen as a final attempt to halt Iraq's plunge into full-scale war between politically dominant Shi'ites and minority Sunni Arabs. TENSIONS Although U.S. forces smashed the Mehdi Army uprisings in 2004, any confrontation with American troops could increase tension among the powerful Shi'ite Alliance bloc that includes Sadr's movement and would embarrass Maliki. Shi'ite Alliance officials said the Sadrists would suffer a setback if they got involved in battles again with U.S. forces. "Entering a street battle will not free their detainees and they know that from experience," said a senior Shi'ite Alliance official. "They are involved in the political process, they get benefits and power for being in the government and in the parliament. Why would they want to risk this?" he asked. Last month Sadr's political movement ended a two-month boycott of parliament and government after it suspended its participation to press demands for a timetable for the withdrawal of U.S. troops from Iraq. No timetable was given. The Sadr movement said it wanted the security plan to work. "We will not give any chance for this plan to fail. We fully support it," said a Sadr movement official. Maliki has said U.S. and Iraqi forces would have the right to go anywhere in Baghdad during the crackdown, including mosques and political party headquarters. American officers say this could include the Mehdi Army's stronghold in the teeming Shi'ite slum of Sadr City, which was left largely untouched in previous, failed crackdowns. Sadr, a fiery cleric, derives much of his authority from his highly respected father, a cleric believed killed by Saddam Hussein's agents. He has also gained popularity by providing services to the poor, creating a vast network of support. "We had to fight a defensive war in 2004 against the occupation forces, but now we are a peaceful resistance," Rubaei said. "We consider politics as a mean to achieve a need -- the liberation of Iraq through peaceful means."
