Shi'ite cleric Muqtada al-Sadr, returning to Iraq after four years of Iran-based exile, has urged his followers to remain calm.
Hundreds of people turned up to greet the radical cleric enthusiastically when he arrived in the holy city of Najaf.
Sadr said in a statement that "Your indiscipline while I was performing my religious rituals bothered me and hurt me. I beg you to be disciplined, and not to shout excessive slogans."
Sadr has so far not explained the reasons for his return from self-imposed exile.
The cleric gained wide popularity among Shi'a in Iraq in the months after the U.S.-led invasion of 2003, and his Imam Al-Mahdi Army battled U.S. troops in several bloody conflicts in following years.
In August 2008, Sadr suspended the activities of the Mahdi Army.
His movement is now a key element in the recently formed government of Prime Minister Nuri al-Maliki.
Sadr made no public appearances. According to his office in Najaf, he will give a speech on January 8 although there was no information on where the speech would be delivered.
compiled from agency reports