The insurgency against the U.S. occupation shook the heart of Baghdad on Monday with a powerful bombing that killed five foreigners and at least eight Iraqis -- all civilians -- and attracted a mob of enraged Iraqi men who screamed their anger at the United States, torched vehicles and vowed to kill any Americans remaining in their country.

Young men jumped on three bombed-out SUVs and smashed them with crowbars before setting them afire in scenes of uncontrolled fury heretofore unseen in the Iraqi capital with its extensive U.S. security. The blast was strong enough to rip the facade off a three-story building beside the street and rattle the Ishtar Sheraton Hotel about a mile away.

The U.S. military identified the slain foreigners as an American, two Britons, a Frenchman and one of unknown nationality. Prime Minister Ayad Allawi, in a televised statement, said they were civilian contractors working to restore Iraq's rickety electricity grid, whose constant failings are one of the Iraqis' main complaints against the 14-month-old U.S. occupation.

Papers found at the scene, written in French and English, described plans for improvements to Baghdad junction boxes by GE Energy Products France SNC. A General Electric spokesman in Brussels, Louise Binns, told the Associated Press that three of those killed worked for a GE subsidiary, Granite Services Inc., and the other two were their security guards.

Jassim Mohammed, director of the nearby Kindi Hospital, said at least five dead Iraqi civilians and 29 wounded were brought to his facility, including passersby and people from nearby blasted-out buildings. Officials at Baghdad's neurological hospital told reporters three dead Iraqi civilians and 14 wounded were brought there.

"This terrorist attack is another cowardly action to attack the Iraqi infrastructure," Allawi said from the headquarters of the interim government in the heavily fortified area known as the Green Zone, surrounded by U.S. troops on the other side of the Tigris River.

As the mob kicked and flailed at the twisted vehicles shortly after the explosion and Iraqi police stood aside, a half-dozen Humvees roared up and U.S. soldiers jumped out. They pointed their M-16 automatic rifles and heavy machine guns at the crowd and, shouting obscenities, ordered onlookers away from the site of the explosion. One Humvee pushed its way into a knot of Iraqis to force them back over a low wall and into neighboring Nation Park.

Most Iraqis did not understand the vulgarities shouted by U.S. soldiers. But they understood the imperative tone and the brandished weapons, and many moved back. Half an hour later, the soldiers climbed back into their Humvees and, after lining up in two rows, drove slowly away from the chaos.

Iraqi police armed with pistols and automatic rifles then tried to restrain the crowd as it surged forward again. But the police, unwilling to fire on fellow Iraqis, were quickly engulfed by the mob and, after being threatened, pulled back while the shouting men burned a homemade American flag, set fire to the vehicles and chanted support for Moqtada Sadr, a Shiite Muslim cleric whose militia, the Mahdi Army, has confronted U.S. troops for weeks.

"Long live Sadr! Long live Sadr!" they shouted in rhythm as they marched down the street as oily black smoke billowed up behind them.

"We can do nothing about this chaos," said a policeman who declined to be identified by name. "These people would eat us if we tried to force them to leave. We have no authority, not enough weapons to protect ourselves. . . . They accuse us of being collaborators, so how can we convince them to obey us?"

The blast was the second fatal bombing in as many days in the Iraqi capital; a suicide car bomb killed 12 people Sunday in another part of the city. It was unclear whether Monday's blast was caused by a street-side device or a bomb-rigged vehicle with a suicide driver. Whatever the method, the explosion left several taxis and other cars strewn about the site next to the blasted SUVs used by the foreigners.

Another bomb, aimed at police cars near Salman Pak about 20 miles southeast of the capital, killed four people Monday, police told the AP.

The continuing bombings -- more than one a day so far this month -- have created a growing impression among Iraqis of chaos and lack of control as the United States prepares to formally hand over limited sovereignty to Allawi's interim government on June 30. U.S. and Iraqi officials repeatedly have speculated that creating such an impression is precisely the goal of those carrying out the violence.

Although no bloodier, Monday's blast in the capital carried significantly more political meaning than its predecessors. It erupted from the point where Saadoun Street flows into Liberation Square, a central Baghdad traffic circle laden with the history of modern Iraq, from heroic sculptures commissioned by the country's former dictator, Gen. Abdul Karim Qassem, after he overthrew the British-imposed monarchy in 1958 to the spot where, one decade and several coups later, Saddam Hussein had 14 Iraqi Jews hanged on espionage charges.

U.S. soldiers, backed by Bradley Fighting Vehicles, had returned and closed off the area by midday, while forensics specialists combed through the charred wreckage. The cordon caused a giant traffic jam as cars spilled off Jumhuriyah Bridge into the square. And it presented passing Iraqis with the spectacle of four U.S. soldiers -- kneeling in the unforgiving sun, their M-16s ready, concertina wire coiled in front of them -- just under the looming panel of carvings that Qassem ordered up to depict Iraq's emergence from foreign domination.

Moreover, the mob of young men who shouted their contempt and anger at the United States, lumping it with Israel as an unredeemable enemy, brought to the capital's center a display of anti-occupation fury previously seen only in outlying trouble spots such as Fallujah, 35 miles to the west, or Najaf, about 90 miles to the south. Men shouting at the top of their voices swore they had seen an Israeli flag in one of the vehicles shortly after the bomb detonated.

Many of the youths who took part, Iraqi witnesses said, came from the nearby Thieves Market, where street vendors, mostly dispossessed Shiites, line the sidewalk to sell their wares from makeshift tables. Poor and young, they have formed a ready pool of supporters for Sadr who clash nearly every day with occupation troops, particularly in the Sadr City slum of eastern Baghdad, and are eager to believe the worst about U.S. intentions here.

"It's all the Americans' fault," shouted Amid Abdi, who displayed a bloody hand he said was wounded when the bomb went off as he walked nearby.

As he talked, a teenage boy, his head shaved close like that of a Marine, stepped up. "We will slaughter them," he said, drawing his fingers across his Adam's apple.

"The bombings happening in Iraq these days are part of the U.S. plan," affirmed Wasam Basim, 24, who works for the Facilities Protection Service, a U.S.-financed corps assigned to prevent attacks such as Monday's. "They are doing these bombings to show the world that Iraq is an unsafe country and they have to stay longer to maintain security. Also, they want to find an excuse not to hand over full sovereignty to the Iraqi government."

Ali Hussein, 32, a member of the same service, accused Iraqi police of paying more attention to the foreigners killed and wounded by the explosion than the Iraqis lying nearby.

"The police are traitors," he declared. "They moved the bodies of the foreigners and left the Iraqis lying in the street. They should all be killed. We have to burn these cars. We have to show them what it means to work against Iraq. This time we'll burn the cars empty. Next time, we'll burn them with their occupants inside."

Allawi, along with Interior Minister Falah Naqib and Defense Minister Hazem Shalan, blamed the bombings and assassinations that have hit Baghdad in recent weeks in part on Abu Musab Zarqawi, a Jordanian accused by the United States of being an al Qaeda terrorist leader fomenting violence against the United States in Iraq.

"The terrorist attack today in the Saadoun neighborhood and the assassinations in the last few days show that the terrorists are trying to stop the sovereignty handover process," Allawi declared. "Zarqawi and his followers, along with others, are working hard to prevent this process."

Shalan suggested things might get better after Iraqis take over security control from the 138,000 U.S. and about 20,000 allied troops. "Everybody knows that the coalition forces are handling security now," he said. "From now on, you will witness a change that will stop these terrorists."

Men jump on a vehicle at the scene of a bombing in Baghdad that killed five foreign contractors and at least eight Iraqis. Rescuers carry a wounded man from the rubble of a building destroyed by the second deadly bomb blast in Baghdad in the past two days.