Sadr City, the capital's teeming Shiite district where Moqtada al-Sadr's Mahdi Army is entrenched, erupted in violence again Sunday, one week after a truce ended battles pitting Mr. Sadr's militia against US and Iraqi troops.
Although sporadic clashes continued between the Mahdi Army and Iraqi forces even after the cease-fire deal, Sunday's flare-up has been the worst and threatens to undo the lull in fighting in the capital and in the southern oil city of Basra.
Police sources cited by Reuters said that at least 22 people were killed and 55 wounded in the battle that started overnight. Although it's unclear what started this latest round in fighting with the Mahdi Army, the US military said it killed nine "criminals" in an assault by one of its helicopters in Sadr City.
The mortar fire on the Green Zone – a constant during the height of fighting with the Mahdi Army – also resumed Sunday.
Inside the vast Shiite slum, home to roughly 2.5 million people, the situation is increasingly tense as the area's squares and apartment blocks are destroyed by Iraqi or American strikes, its streets used as Mahdi Army positions, and its residents increasingly caught in the middle of this fight.
On a visit Sunday during the fighting, this reporter witnessed the devastating toll on a district that remains besieged by US and Iraqi forces.
On Sunday, a convoy of US Abrams tanks and Bradley and Stryker combat vehicles patrolled at the entrance of Sadr City as dozens of Iraqi soldiers took positions on balconies.
Once inside the district, people shouted, "Quick, run into the alleyways."
Two artillery shells hit nearby, probably fired from the US tanks. Dust and smoke rose in the distance. A newly issued Iraqi Army Humvee emblazoned with the Iraqi flag was on fire farther down the road.
One of the teenagers milling around said: "This belongs to the dirty bunch."
Deeper into Sadr City, it was militia territory. Young militants were everywhere. They carried sniper rifles, machine guns, and rocket-propelled grenade launchers. They were on street corners and rooftops ready to fend off any advance by US and Iraqi forces.
"Watch the [US] airplanes … they are killing civilians and civilians are everywhere," shouted a fighter dressed in military fatigues.
Every now and then, a civilian shouted: "Raise your hands in the air so they do not shoot at us."
Two fighters ran out. "They have just struck the home of Abu Rahman, and they killed three members of his family," said one.
A man who appeared to be the leader of this group hugged the fighter, and they both broke out in tears. "No, they were not killed," said the presumed leader.
"I saw their blood with my own eyes," responded the fighter.
The offices of Sadr's movement offered relative safety. The muezzin in a nearby mosque was already calling for the noon prayers. Inside, fighters prayed.
Since the start of the war, it's routine for all journalists venturing into Sadr City or other areas controlled by Sadr's Mahdi Army to seek out media coordinators. On Sunday, the one in Sadr City wasn't there.
Several other mortar rounds went off nearby. It was time to get out. More mortars were going off – seemingly everywhere. Another explosion sent a plume of black smoke from a rooftop.
Two men came out of the building carrying two children – they appeared to be dead or unconscious.
"Quick to the hospital, their injuries are serious," shouted one of the men as he hopped into a taxi outside. Several ambulances sped by, probably taking the wounded out of Sadr City to better facilities elsewhere in the capital.Later, residents said, several food warehouses in the district's vast Jamila market were on fire. A plume of black smoke was seen rising from that area.
• Correspondent Sam Dagher contributed from Baghdad.