The leader of the main Shia militia in Iraq yesterday ordered most of his followers to disarm and focus on social work, leaving an elite contingent to continue the fight against US forces if a clear timetable for their withdrawal is not drawn up.

Hojatoleslam Moqtada al-Sadr, the charismatic Shia cleric, had his message delivered to large crowds of worshippers after Friday prayers in the Baghdad Shia slum of Sadr City, a stronghold of the notorious Mahdi Army. An American flag was burnt as protesters shouted: “No, no to America! No, no to occupation!”

Despite the heightened emotions, members of al-Mahdi Army – which has been blamed for much of the bloodshed in Iraq since the invasion – appeared receptive to the idea of laying down their arms and pursuing more peaceful aims.

Mr al-Sadr said that an elite unit of fighters would remain but that the Mahdi Army would be completely dissolved once the US began a timetabled withdrawal.

“Weapons are to be exclusively in the hands of one group, the resistance group,” Mudhafar al-Moussawi, a Shia cleric, said. Another group, called Momahidoun, would focus on social, religious, educational and community work.

Although details of the plan corresponded with previous announcements by Mr al-Sadr as he attempts to reorganise his group, this one comes at a sensitive time in negotiations over the US presence in the country.

Baghdad and Washington are locked in discussions over a long-term security pact, which will provide a legal basis for American troops to operate in Iraq when the current UN mandate expires at the end of the year.

Iraqi officials have been quoted as saying that they want all US combat troops out of the country by October 2010 – a timeline also advocated by White House hopeful Barack Obama.

President Bush has refused to set a firm timetable for withdrawing the 144,000 US troops left in the country but spoke last month of a “time horizon” for a pullout.

Abid Abu Zahraa, a local al-Mahdi Army leader, said that his men always followed the orders of their spiritual leader. “We carry our weapons according to the orders of our leader. We abandon our weapons when he orders us to do so.” He added that al-Mahdi Army already carried out social and educational work.

“After receiving orders to concentrate on such matters, I believe that this area of activity will grow and will serve the citizens of Iraq.”

Al-Mahdi Army launched two uprisings against US forces in 2004. Mr al-Sadr backed the rise to power of Nouri al-Maliki, the Prime Minister, in 2006 but split with him last year over the timetable issue of a US withdrawal.

Over the past few months Mr Maliki has launched several largely successful crackdowns against militias, including al-Mahdi Army. An offensive in the southern city of Basra in March and April reclaimed the city from militia hands.

Salah al-Ubaidi, the spokesman for the cleric, said that while the resistance would not end until US troops left Iraq, the cleric was ready to take positive steps if Washington moved in the right direction.

“If we find [this does not happen] and the US forces change their stance over the timetable, we can change direction also,” he said. “This will not mean ending the ceasefire, it will depend on what’s going on on the ground.”

Mr al-Sadr announced a ceasefire for his militia a year ago, which is cited as one of the main reasons behind a drop in the violence in Iraq to its lowest level in four years.

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