Iraq's radical Shiite cleric Moqtada al-Sadr on Wednesday ordered his Mahdi Army militia to suspend its activities for six months in a bid to reorganise the militant group.
"I direct the Mahdi Army to suspend all its activities for six months until it is restructured in a way that helps honour the principles for which it is formed," Sadr said in a statement issued by his office in the city of Najaf.
His order comes after intense clashes in the nearby Shiite shrine city of Karbala on Tuesday left at least 52 people dead and 300 more wounded which witnesses said involved policemen and suspected Mahdi Army fighters.
Sadr aides have denied any involvement of his militants in the clashes that erupted during a major Shiite festival and sent hundreds of thousands of pilgrims fleeing.
On Wednesday, Sadr also ordered a three-day period of mourning for victims of the clashes and called on Iraqi authorities to launch an investigation.
"The investigations should be just and neutral so that the tragedy would not occur again," he said.
The thousands-strong Mahdi Army has been implicated in the death-squad killings of Iraqi Sunni Arabs over the past 18 months since a brutal sectarian conflict broke out last February.
In December, the Pentagon identified the militia as the biggest threat to stability in the war-ravaged country, even ahead of Al-Qaeda in Iraq, the local affiliate of Osama bin Laden's network.
Sadr responded by dropping out of sight and ordering his followers not to resist a joint US-Iraqi crackdown to restore stability to Baghdad, the epicentre of the communal bloodletting, since February 2007.
Most of his fighters in the capital are reported to have disappeared to avoid the military crackdown and taken shelter in the Shiite south of the country.
The militia has also suffered from allegations of being involved in clashes with rival Shiite militias, particularly the Badr Corp, the military wing linked to Supreme Iraqi Islamic Council, the party led by powerful politician Abdel Aziz al-Hakim.
The movement has been working hard to bolster its nationalist and anti-American credentials, something Sadr was always known for before his more recent alleged associations with sectarian death squads.
But some say the cleric is battling to retain his tenuous hold on his militia leaders, many of whom the American military believes have broken away from the main group.
Hundreds of Shiite fighters from the Mahdi Army have been killed or captured by the US military since the nationwide security assaults were launched earlier this year.
The US military claims that most of the targeted individuals from the militia are "rogue" elements who have broken away from the main faction.
It says these militants have formed special groups who are trained by Iranian-linked groups to kill US-led troops in Iraq. Tehran denies the charge.