BAGHDAD, April 6: Iraqi government troops backed by US forces swept into the Sadr City slum at dawn on Sunday, triggering the worst violence in Baghdad since cleric Moqtada al-Sadr called his fighters off the streets a week ago.

Police said at least 22 people had died in the fighting.

Officials at Sadr City’s two hospitals said at least 16 bodies had arrived and 78 wounded people were treated.

Iraqi army troops were moving through two southern sectors of the locality, said US military spokesman Lt-Col Steven Stover. US helicopters fired at least two Hellfire missiles, killing nine fighters, he added.

The fighting follows a week of relative calm after a crackdown by the Iraqi government on Sadr followers led to battles across the capital and the south late last month.

The unrest comes only days before US Ambassador Ryan Crocker and US commander Gen David Petraeus are due to deliver key testimony to the US Congress on progress in Iraq.

Police said a joint operation by the US military and Iraqi forces had started in the early hours of Sunday. Gunfire could be heard throughout the day in Sadr City, the bastion of Sadr’s Mehdi Army and home to 2 million people in eastern Baghdad.

“I have lost my cousin in these clashes today. I think Maliki will be happy now,” a Mehdi Army street commander who gave his name as Abu Ammar told Reuters.

STUDENTS FREED: Near the northern city of Mosul, at least 40 students on a bus were kidnapped by gunmen for several hours before Iraqi security forces got them freed, said Brig-Gen Khalid Abdul-Sattar, security spokesman for the Nineveh province.