Mahdi Army fighters loyal to Shia cleric Moqtada al-Sadr have seized the centre of the city of Nassiriya in southern Iraq.
A four-day-old Iraqi army crackdown on Sadr's Mahdi Army in Basra, Iraq's second city, has sparked fighting across the south and in Baghdad. An Iraqi commander said today at least 120 "enemy" fighters have been killed and 450 have been wounded in the Basra operation.
In the capital, Iraq's parliament was due to hold an emergency session in a bid to end violence in Basra, where Prime Minister Nuri al-Maliki gave militants a new deadline to hand over their weapons. Militants have also taken control of the town of Shatra, 40 kilometres to the north of Nassiriya.
Authorities have imposed a three-day curfew in Baghdad to contain the violence, in which more than 150 people have been killed since the government began the offensive on Tuesday against Sadr's followers.
The assault on Basra has exposed deep divisions between rival factions within Iraq's majority Shia community. It is also a major test for Mr Maliki's ability to prove Iraqi forces can stand on their own and allow US forces to withdraw.
Mr Maliki on Wednesday gave militants in Basra 72 hours to surrender themselves and their weapons, but today extended the deadline for handing over the weapons until April 8th.
Sadr, who helped install Mr Maliki in power after an election in 2005 but later broke with him, has called for talks with the government. But Mr Maliki has vowed to battle what he calls criminal gangs in Basra "to the end".
The clashes have all but wrecked a truce that Sadr imposed on his Mahdi army last August, which Washington had said helped curb violence.
US President George W. Bush has praised Mr Maliki's "boldness" in launching the operation, the largest military campaign carried out yet by Iraqi forces without US or British combat units.
Sadr's aides say his ceasefire is still formally in place, but his followers have staged a "civil disobedience" campaign, forcing schools and shops to shut, and Sadr has threatened to declare a "civil revolt" if the crackdown is not halted.