NAJAF, Iraq (Reuters) - A mixture of euphoria and cautious hope greeted anti-US Shia cleric Moqtada al-Sadr on Thursday, a day after his return to Iraq from exile, and many Iraqis looked to him to help stabilize their war-torn country. Hundreds of Sadrs followers in the holy city of Najaf celebrated his homecoming from Iran, and the possible transformation into a mainstream politician of a man once associated with black-clad death squads that roamed Iraq. Sadr cemented his movements position in the new coalition government after playing a crucial role in putting Prime Minister Nuri al-Maliki back in power for a second term. His return was possible also because of declining US clout ahead of a full military withdrawal by the end of this year. Sadrs support of Maliki is thought to have been brokered in part by Iran, and his years in exile under Iranian patronage may have increased Tehrans influence on him. But diplomats say he is ultimately an Iraqi nationalist, and an unpredictable and enigmatic leader unlikely to heed the wishes of others. In Baghdads sprawling Shia slum of Sadr City, a Sadr stronghold, many rejoiced. We Iraqis are delighted at the return of Sayyed and leader Moqtada al-Sadr, above all because he is now part of the political process, said Sadr City resident Salih al-Daraji. Sadr, who met some tribal leaders on Thursday, chastised his followers for the jubilant welcome he received on Wednesday, saying it could hurt his reputation. His statement suggested that he wanted to put what critics called his rabble-rousing past behind him and anchor himself and his movement in a more mainstream position. The lack of discipline of some of you during my performance of religious rituals and public matters bothers me and harms me, so I hope that you will exercise discipline and stop the excessive chants and stampedes, Sadr said in a statement. Sadrist officials said he had indicated he planned to remain in Iraq, but Sadr himself made no announcements. His officials say the government has guaranteed his safety and freedom from arrest. Politicians, both allies and former foes, welcomed Sadr, saying his return showed his support for the government. The return of the Sayyed Moqtada al-Sadr to Iraq shows evidence of peace and security in the Iraqi political atmosphere generally, said Mustafa al-Hiti, a leader in the Iraqiya bloc, which is heavily supported by minority Sunni Muslims. The Sadrist movement secured 39 seats in the new parliament and has seven ministries in Malikis new government. Sadrs Mehdi Army militia was once seen by the United States as the biggest threat to Iraqs security. The group, which says it has laid down its arms, was crushed by Iraqi and US forces in 2008 and Sadr has forbidden it to commit violence against other Iraqis. I am sure there are people who are trying to taint the reputation of the Mehdi Army and the Sadr movement because we entered the political process, said Fadhil Issa, 50, a jobless Baghdad resident who traveled to Najaf to see Sadr. We, as the Mehdi Army and the Sadr movement, support the security forces, and things of the past will not be repeated. Maliki warned in Baghdad in a speech marking armed forces day no one would be allowed to tamper with Iraqs security. Our (security) apparatus, our army, our political forces, our citizens, all stand ready to confront any challenge or any breach of our internal security or external security, he said, without naming any person or group. While diminished in stature by years of self-imposed exile, Sadr retains a zealous following among the young and poor. He fled Iraq in 2006 or 2007 to escape an old arrest warrant, and is believed to have pursued religious studies in Shia Iran. God willing, the political process will continue with his return, and reconstruction will begin because of it, said Sadr City resident Mohammed Khalef.