BAGHDAD - It was just another car bomb, this time an old, blue Volkswagen Passat that blew up in a busy shopping district of Baghdad, one of four that killed and maimed Iraqi civilians Monday.

But the array of first responders who descended on the smoke-filled scene exemplified how militants aren’t the only force that’s undermining the plan to restore order to the violent Iraqi capital.

After the blast near a busy shrine in the mostly Shiite Muslim area of Karrada, Iraqi firefighters, medical workers, Iraqi police, traffic police, Iraqi soldiers, American troops, members of two powerful Shiite militias and ordinary residents jostled for control. With so many forces picking through the charred, bloody wreckage, no single group emerged as the one in charge, and the already frenzied scene spiraled into pandemonium.

The bombings occurred on the eve of long-anticipated talks between U.S. and Iranian officials on ways to reduce the rampant bloodletting in Iraq. Three parked cars, including the Volkswagen, blew up within an hour Monday morning; a fourth detonated that afternoon outside a Kurdish restaurant near an entrance to the fortified Green Zone.

Iraqi officials said at least 18 people died and more than 40 were injured in those bombings. Two smaller explosions - one on a minibus and one near a police station - killed another Iraqi and wounded 11. Police announced that 24 corpses had been discovered throughout Baghdad.

At the scene near the shrine in Karrada, Iraqi firefighters turned their hoses on smoldering vehicles as medics attended to the injured or recovered the dead. Iraqi police interviewed one set of witnesses while Iraqi soldiers questioned another batch. U.S. troops, who arrived in a convoy of Humvees, shooed away all the bystanders, including other possible witnesses.

Two unarmed Mahdi Army militiamen barred a journalist from photographing the scene, even though government authorities said they had no objection to the photos. Three self-described members of a so-called popular committee, the neighborhood patrols established by the Iranian-backed Badr Organization, set up their own checkpoint about 100 feet from where U.S. and Iraqi authorities had gathered.

Neighborhood residents, skeptical of all the security forces’ abilities, took it upon themselves to record license-plate numbers in their personal notebooks. Some residents even began collecting shrapnel and other evidence, launching their own “investigation.”

When the civilians overheard two Iraqi police officials recording what they considered an incorrect version of events, the locals yelled at the authorities and tried to block them from viewing the blast site.

“They put in that police checkpoint and it wasn’t useful,” said Ali Yousef, who survived the bombing with minor injuries; his computer shop was destroyed. “They brought in more police, and it didn’t stop them. I think there’s nothing that can stop this.”

Another witness, a bespectacled professional who asked to be identified only by his first name of Haider because of fear for his safety, waved his arms and cursed the Iraqi government and security forces, whom he described as puppets of the U.S.-led occupation.

“We don’t have a government! It’s worthless,” Haider yelled. “Bring me one honest man from the Sunnis or the Shiites!”

An elderly woman in a white head scarf and colorful robes glared at the American troops who arrived at the scene, less than a half-mile from a bridge leading into the Green Zone compound, after the dead and injured had been retrieved. The firefighters already had extinguished the blaze.

“Why are they killing us? We have no one left!” the old woman, who identified herself only as Umm Hussein, began to shout. “They aren’t saving anyone, they’re killing civilians. And who’s behind this?”

She pointed to the American soldiers.

A man who said his relatives had been killed in a previous bombing in Karrada seethed as he surveyed the jumble of uniformed officials at the scene.

“What have we gained?” he screamed. “Damn religion! Damn prayers! Who’s going to bring back my father and uncle?”

Other residents led the man away, sharply warning him against blasphemy.

The latest violence came ahead of a meeting of Iranian, American and Iraqi officials scheduled for Tuesday in the Green Zone. The negotiating teams are expected to include the Iranian and American ambassadors to Baghdad.

Earlier, some Iraqi officials had complained that they were being sidelined; another example of overlapping forces at play in Iraq. It was later agreed that Iraqi officials would observe the talks, though U.S.-Iranian interests would take center stage.

“I have no illusion that the erosion of confidence between the two (nations) is so deep it will take some time,” said Iraqi Foreign Minister Hoshyar Zebari, who was instrumental in arranging the gathering.

The meeting will be the second since late May. The U.S. military has accused Iran of arming Iraqi militants and teaching them how to make a particularly lethal, armor-piercing bomb called an explosively formed projectile. Tehran has denied the allegations.

Iranian officials are expected to renew their calls for the release of five Iranians whom the U.S. military has detained on suspicion of arming and training Shiite militants in Iraq. Iran says the five men are diplomats and had full permission to enter Iraq.

Al Dulaimy is a special correspondent for McClatchy Newspapers. Leila Fadel and special correspondent Laith Hammoudi contributed to this article.

McClatchy Newspapers 2007