The Iraqi government and the US forces on Thursday welcomed the decision of radical Shia cleric Muqtada al-Sadr to suspend for six months armed operations mounted by his Mahdi Army militia.  This applies to attacks on Iraqi security forces as well as US troops.

Sadr took this action after elements of his militia were accused of rioting and firing indiscriminately on a Shia pilgrims assembled in Kerbala to celebrate the birthday of Muhammad al-Mahdi, the final imam of the Shia sect.

Fifty-two people were killed and scores wounded in fighting said to between the Sadrists and securitymen recruited from the rival militia, the Badr Corps of the Supreme Iraqi Islamic Council (SIIC).

Violence reportedly erupted when police and securitymen cleared a route through the crowd for the convoy of SIIC leader, Ammar al-Hakim, which was traveling to the Shrine of al-Hussein, the grandson of Prophet Muhammad.

Washington, which regards the Mahdi Army as the greatest threat to the stability of Iraq, was relieved while the government of Nuri al-Maliki, which depends on the backing of SIIC and the Badr Corps, called Sadr’s move “very good news”.

Sadr said he expects to root out “rogue elements” from the ranks of his militia, which has a core membership of 50,000 to 60,000 fighters. But thousands of other Shia gunmen claim they are loyal to Sadr.

Since the Sadrists are largely blamed for sectarian cleansing and murders of Sunnis in Baghdad, operations against US troops in Shia towns and villages in the centre of the country, and attacks on British forces in the south, a freeze on Mahdi army activities could reduce violence significantly. But only if Sadr himself is able to assert control over his unruly forces.

The Mahdi Army and Badr Corps have been battling for months in the south and the Shia holy cities of Najaf and Kerbala.

There are dynastic and geo-political dimensions to the feud.  Muqtada al-Sadr is the son of Grand Ayatollah Muhammad Sadiq al-Sadr, a populist cleric who created a large network of institutions to help the Shia poor.

By staying in Iraq and working within the limits set by the Baathist regime, Sadr, who was eventually assassinated, became a competitor of Ayatollah Muhammad Baqr al-Hakim, who was living in exile in Tehran and founded SIIC and the Badr Corps.

After the US occupied Iraq, Muqtada al-Sadr — who remained in the country during the Baathist regime — became the standard-bearer of nationalist Shias who opposed foreign rule.

Hakims, who returned to Iraq on US tanks, represented Iranian interests but were dependent on the US military might to remain in power. The Mahdi Army and Badr Corps militiamen have been incorporated into Iraq’s forces, making them factional, unreliable and susceptible to intra-Shia violence.