Iraqi government appeals for calm

Sadr's Mehdi Army is believed to have some 60,000 fighters

The Iraqi government has called on other militant groups to follow the example of Moqtada Sadr's Mehdi Army militia and freeze their activities.

In a statement, the office of Prime Minister Nouri Maliki welcomed Mr Sadr's order to stop armed action for a maximum period of six months.

Officials appealed to all armed groups, both Sunni and Shia, saying it was "a good opportunity" to halt attacks.

They argued that this would preserve Iraq's "integrity and sovereignty".

But the BBC's world affairs correspondent Mike Wooldridge says that in reality the government does not anticipate reaching any understanding with the group it considers to be the most extreme of all - al-Qaeda in Iraq.

There has also been some ambiguity about how the tens of thousands of members of the Mehdi Army will interpret the six-month freeze declared in order to "rehabilitate it in a way that will safeguard its ideological image".

In Sadr City, a Shia district in north-east Baghdad, residents told the Associated Press on Thursday there was no sign of Mehdi militiamen, who normally cruise the streets in cars and converge on Mr Sadr's office in the evening.

But a senior Sadr aide said on Thursday that the order to stop armed actions might only last a week if American and Iraqi forces did not stop detaining the cleric's followers.

Gun battles

Militiamen loyal to Mr Sadr were widely blamed for clashes on Tuesday which left more than 50 dead and 200 injured, according to police.

The freeze came after clashes in Karbala killed more than 50 people

The fighting cut short a major religious festival in Iraq, which had drawn hundreds of thousands of Shia pilgrims to the holy city of Karbala.

But Mr Sadr has denied any involvement in the violence, and Mr Maliki's office was at pains to stress that it was not accusing Mr Sadr's men of responsibility for the carnage in Karbala.

The statement said government forces were not targeting Mr Sadr's followers in Karbala in the wake of the violence, an apparent reference to the detention of more than 70 people.

"The Sadr movement is an important political power in Iraq and will remain active in the political process," the premier's office said.

"The measures taken by the government following the tragic events in Karbala do not point the finger at the Sadr movement."

"The government will only chase after those elements who committed the crimes."