Iraqi troops backed by US forces battled gunmen in Baghdad's Sadr City yesterday in the heaviest fighting in the capital since Shi'ite cleric Moqtada al-Sadr pulled his militiamen off the streets a week ago.
Police said at least 22 people were killed in the clashes. Officials at Sadr City's two hospitals said at least 16 bodies had been brought in while 78 wounded people were treated.
Iraqi soldiers were moving through two southern sectors of the Shi'ite slum and stronghold of Sadr's Mehdi Army militia, said US military spokesman Lieutenant-Colonel 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 Prime Minister Nuri al-Maliki on Cleric Sadr followers led to battles across the capital and the south late last month.
The unrest comes two days before US Ambassador Ryan Crocker and US commander General David Petraeus are due to deliver key testimony to the US Congress on progress in Iraq.
Police said the joint US-Iraqi military operation began early yesterday. Gunfire could be heard throughout the day in Sadr City, home to two million people in eastern Baghdad.
Lieutenant-General Abboud Qanbar, head of the Iraqi military in Baghdad, reiterated an order from Mr Maliki for all armed groups to hand in their weapons.
"If they refuse to surrender their arms, we will confiscate them," Lt-Gen. Qanbar told reporters at a police station in Sadr City.
Mehdi Army fighters bristled at the raids. "I have lost my cousin in these clashes today. I think Maliki will be happy now," a Mehdi Army street commander giving his name as Abu Ammar said.
US Apache helicopter gunships swooped overhead and a column of black smoke towered over the Jamila market, a vast bazaar on the edge of the slum that supplies food for much of the eastern half of the capital.
"Criminals fired rockets and they hit the Jamila market. I don't know how many people they killed," Lt-Col Stover said. An Interior Ministry source said the fire blazed unchecked for hours because fire-fighters were unable to reach the market.
US and Iraqi forces have imposed a blockade on vehicle traffic in and out of Sadr City for two weeks. Residents of the besieged district describe skyrocketing food prices, rubbish piling up and claustrophobia from being trapped indoors.
"We haven't been able to sleep since this fighting started two weeks ago," said Wardan Ali, a student from Sadr City forced to walk 10 kilometres on foot each way to university because of the blockade.
Cleric Sadr's bloc in Parliament denounced the raids.
"The intervention of US forces is horrible and unjustified. Some people in Sadr city believe these forces will hunt and kill them," said Hassan Hashem, a Sadrist member of Parliament's security committee.
Near the northern city of Mosul, at least 40 students on a bus were kidnapped by gunmen for several hours before Iraqi security forces freed them, said Brigadier-General Khalid Abdul-Sattar, security spokesman for Nineveh province.
The incident was a reminder of continuing unrest in the mixed and Sunni Arab areas of the north at a time when attention is focused on violence in Shi'ite areas in Baghdad and the south.
"These are terrorist groups linked to al Qaeda and Saddam's former regime who are terrorising innocent people constantly," government spokesman Ali al-Dabbagh told Al Arabiya television.
Sunni Islamist al Qaeda has regrouped in northern provinces after being pushed out of western Anbar province and Baghdad by a series of military offensives. The US military says Mosul is al Qaeda's last major urban stronghold in Iraq.
Sunday's fighting in Sadr City followed a joint call by Iraq's main factions, apart from the Sadrists, for all militias to hand over weapons, an apparent attempt to isolate Shi'ite cleric Sadr but who has called for one million Iraqis to march against US "occupiers" on Wednesday, when Ambassador Crocker and US Commander Petraeus are due to conclude two days of testimony before the US Congress.
The two top US officials in Iraqi are expected to call for a pause in American troop withdrawals after 20,000 US soldiers return home over the next four months.