Shiite militiamen flooded a Baghdad neighborhood Sunday, setting up checkpoints and singling out and killing at least 36 young Sunni Arab men in a spasm of violence that pushed the city deeper into sectarian warfare.
The execution-style killings also set off a political firestorm. One Sunni leader accused the government of negligence, but Iraqi Prime Minister Nouri Maliki, a Shiite, played down the events, insisting that the "situation in Baghdad is under control."
As dusk settled, a pair of car bombs, apparently set off by Sunni Arab insurgents, damaged a Shiite mosque in a northern Baghdad neighborhood, killing at least 19 worshipers and wounding 59.
And this morning, two explosions rocked the heavily Shiite Sadr City neighborhood in eastern Baghdad near a row of shops selling used car parts. Initial reports said seven people were killed and 17 wounded.
The violence Sunday came the same day the U.S. military announced that four more American soldiers had been charged with raping and killing a young Iraqi woman and slaying three members of her family in March. The four were charged with rape and murder; a fifth soldier was charged with dereliction of duty. None was named.
Last week, a former U.S. Army private, Steven D. Green, was charged with rape and murder in federal court in Charlotte, N.C. He pleaded not guilty.
The sectarian violence underscored a dramatic worsening of security in the capital even after the formation of a government in May and the imposition of a massive security operation by Iraqi troops and police. It also raised fears that the beleaguered country might soon dissolve into civil war.
Sunni Arab politicians, who have threatened to pull out of the nascent government, blamed the violence on Shiites, demanding that security forces crack down on militias, which are believed to operate in part out of the security services.
"Acts of militias are now being expanded in Baghdad, and they have become a source of concern and harm to people," said Iraqi Vice President Tariq Hashimi, the head of the largest Sunni party, adding that the government needed to "safeguard the lives of the innocent, who have become targets for these militias."
Violence in the religiously mixed Jihad neighborhood began after a suicide bombing Saturday night near the Zahra Shiite mosque killed at least eight worshipers and passersby, officials said.
Sunday morning, militiamen began roaming the neighborhood and setting up checkpoints, asking those trying to pass to show their identity papers, which give name and tribe -- clues to whether the bearer might be Sunni or Shiite.
One witness, who asked not to be identified, said Shiite gunmen took to the streets about 7 a.m. and established a roadblock a short distance from his home. He said a Sunni neighbor was loaded onto a bus filled with gunmen after he showed his identity papers.
"There have been some problems in this neighborhood," the witness said. "But it never reached killing because you showed the wrong identification card."
By midmorning, a number of bodies were strewn about the streets and Sunni insurgents set up their own roadblocks nearby in retaliation.
An official at a hospital where bodies were taken said at least 36 young Sunni men were killed, often pulled from their homes or vehicles. Also among the dead from the Jihad fighting was a Shiite family of five -- a mother and four children -- who were killed when gunmen tossed a grenade into their home, hospital officials said.
At midmorning, Iraqi and American troops sealed off the area, with helicopters whizzing above. The neighborhood is a short distance from the U.S. military headquarters, located next to Baghdad International Airport.
The city is racked daily by other forms of violence, including car bombs and roadside explosive devices. A car bomb detonated in the Shiite slum of Sadr City last week killed 62 people. Kidnappings have become routine, with victims often killed and dumped on the side of the road.
A number of Shiite and Sunni mosques have been attacked in recent days, each apparently in reprisal for the other. The minority Sunnis have accused the Shiites of having death squads allied with Baghdad police.
In the aftermath of the killings Sunday morning, the prime minister's office issued a brief statement saying that some media reports had overstated the seriousness of the situation.
"The situation in Baghdad is under control and the concerned apparatuses are dealing with what is going on," the statement said.
But other political and religious leaders lashed out at the government.
Muthanna Harith Dhari of the hard-line Sunni Muslim Scholars Assn. said the bombing of the mosque Saturday was only a pretext for the slayings that went on the next morning.
He blamed the Al Mahdi army, a Shiite militia, for shootings at checkpoints and for dragging Sunnis from their houses and killing them. He said Sunnis who survived the rampage were told by Shiite friends that Al Mahdi fighters were behind the attacks.
Radical Shiite cleric Muqtada Sadr, who oversees the Al Mahdi militia, called for a special session of parliament to be called by the "alleged independent government" to save Iraqis from "the seas of blood, car bombs and displacement."
"Why don't you convene an emergency session for the sake of your people?" he asked in a prepared statement, saying it was up to all Muslims to "repel the American terrorism working to devastate and provoke sedition."
Sadr made no mention of the Al Mahdi army or its alleged role in the violence, calling instead on "political and religious forces to hamper the Western scheme of patronizing a civil war between brothers."
Iraqi President Jalal Talabani, a Kurd, described the nation as being "upon a dangerous edge." He called on Iraqis to remain calm and avoid any immediate response to the killings, but also to be watchful.
"What happened today requires us to be honest with ourselves and others to condemn these horrendous actions loudly," he said Sunday.
Gen. Wafiq Samarra, an advisor to the president on security affairs, said the government had not lost control of Baghdad but that there were pockets of resistance that needed to be confronted.
"There is a firm decision to confront terrorism and violence, no matter what side they are affiliated with, no matter whether these powers were Sunni or Shiite," he said.
Meanwhile, two clerics from the Sunni Muslims Scholars Assn. were killed Sunday in Samarra while driving from a mosque. Another car pulled alongside, and gunmen dressed in camouflage and black masks shot the clerics and sped off. Officials in the increasingly violent northern city of Kirkuk said at least four police officers and civilians had been killed there.