A car bomb tore through a convoy Monday in central Baghdad, killing 13 people, including an American and four other foreigners working to rebuild Iraq's power plants. A crowd gathered, shouting "Down with the USA!" and dancing around a charred body.

The dead included three employees of Granite Services Inc. (search), a wholly owned, Tampa, Fla.-based subsidiary of General Electric, and two security contractors, said GE spokeswoman Louise Binns in Brussels.

Passions boiled over as the crowd of youths taunted American troops and Western journalists who rushed to the scene near Tahrir Square (search). American troops beat one man with a stick, but after failing to restrain the crowd, the troops and police withdrew.

One civilian bystander — missing a finger from the bomb — ran up to Western reporters and shouted at them to leave.

The blast, which destroyed eight vehicles and turned nearby shops and a two-story house to rubble, is the second bombing in as many days to kill a dozen people and comes nearly two weeks before the formal end of the U.S.-led occupation,

"Nothing is more important than the safety of our employees and those supporting our efforts," Binns said in a statement. "We have taken extraordinary measures to keep them safe and we will continue to work with the Coalition Provisional Authority (search) and Iraqi authorities to protect our people. We remain committed to the reconstruction of Iraq."

Some of the victims were in shops devastated by the blast. One elderly Iraqi man, still wearing bloodsoaked night clothes, was carried from the destruction.

Frantic Iraqis scooped up the wounded and loaded them into private cars to be taken to hospitals.

The bomb killed eight Iraqis and five foreigners, according to an official at the Interior Ministry, speaking on condition of anonymity.

The U.S. military said the dead included two Britons, one Frenchman, one American and a foreigner of undetermined nationality. More than 60 people, including 10 foreign contractors, were injured, the military said.

The bomb went off as three SUVs carrying the contractors were passing through the square. Five other vehicles were also destroyed. Scattered around one of the damaged SUVs were manuals that appeared to be for energy turbines, including one titled, "GE Energy Products, Europe."

The attack unleashed fresh anger at the United States, with crowds chanting "Down with the USA!" and burning an American flag.

"We deplore this terrorist act and vow to bring these criminals to justice as soon as possible," Prime Minister Iyad Allawi (search) said.

He said the foreign victims were helping to rebuild power plants.

Restoring stable electricity supplies is considered a benchmark of progress for Iraq's American rulers since they toppled Saddam Hussein's regime in April 2003. But the struggle has been beset by sabotage by insurgents, and electricity in Baghdad is flowing at less than half of prewar levels

A coalition spokesman said Iraq needs at least 7,000 megawatts of electricity, and engineers hope to get 6,000 megawatts online by midsummer.

GE booked $450 million in orders last year and has projected $1 billion to $3 billion in business in Iraq by next year, according to company spokesman Gary Sheffer. Earlier in the year GE had suspended some operations because of escalating violence, saying that tighter security requirements had caused projects to be delayed.

In March, gunmen killed a Briton and a Canadian who were working as security guards to protect foreign engineers working for GE.

Capt. Issam Ali, security officer at the Neurological Hospital, said three dead and 14 injured had been brought there Monday, many with serious burns and lost limbs. Al-Kindi Hospital reported receiving 29 injured.

Police said that a car bomb also went off Monday near the town of Salman Pak southeast of Baghdad when a gray Opel drove between police vehicles and exploded, killing four people and injuring four others. However, the report could not be indepedently confirmed and police were unable to provide a detailed report of the incident.

There have been 17 car bombings and a near-daily string of other attacks in Iraq this month. On Sunday, 12 people were killed by a car bomb near a U.S. garrison in Baghdad, and gunmen assassinated another member of the new Iraqi government, an Education Ministry official.

The bloodshed has stunned Iraq's new government, which had hoped to gain public support. U.S. authorities had feared an escalation of violence before the June 30 handover of sovereignty, and they wanted the recent establishment of a sovereign government to drain support for the insurgency, allowing security to improve so that balloting for an elected administration can be held by the end of January.

Two members of the interim government have been assassinated since its establishment June 1. Kamal al-Jarah, 63, an Education Ministry official in charge of contacts with foreign governments and the United Nations, was fatally shot outside his home Sunday; and Deputy Foreign Minister Bassam Salih Kubba was gunned down while driving to work Saturday.

Two other top Iraqi officials — both with the police force — narrowly escaped death over the weekend.

Allawi accused Jordanian-born terrorist Abu Musab al-Zarqawi (search) of trying to disrupt the transfer of sovereignty.

"Al-Zarqawi and his followers are earnestly working to prevent the success of this measure," he said.

"I want our people to be patient this month against those forces which are trying to assault them, and I promise the people that we are going to get rid of them and victory will be ours to build the a free and decent Iraq life."

Rather than going after top government figures who are well protected, the insurgents appear to be targeting middle and upper level officials who lack adequate security.

Also Monday, U.S. Marines made a rare trip into Fallujah — only their second visit to the restive Sunni Muslim stronghold since they relinquished control to a local security force. Iraqi forces lined the streets as about 10 Marine vehicles rolled into the city for meetings at the mayor's office.

Marines besieged Fallujah, west of Baghdad, for three weeks in April after four American civilian contractors were killed in an ambush and their bodies mutilated. Ten Marines and hundreds of Iraqis, many of them civilians, died in the fighting, which unleashed widespread criticism among Iraqis, foreign governments and even America's coalition allies.

The siege was lifted when Marines announced a deal to create the Fallujah Brigade, commanded by officers from Saddam's army, to patrol the city.

Elsewhere, the U.S. military released hundreds of prisoners Monday from Abu Ghraib (search) prison, the focus of the scandal over U.S. abuse of Iraqi detainees.

The release — the fifth major one since the scandal broke — came a day after the U.S. military pledged that as many as 1,400 detainees will either be released or transferred to Iraqi authorities by June 30. The Americans will continue to hold between 4,000 and 5,000 prisoners deemed a threat to the coalition.

An official of the International Committee of the Red Cross, meanwhile, said Saddam must be released by the end of the occupation — June 30 — if he is not charged.

Under international and military law, prisoners of war and civilian internees should be released at the end of the conflict and occupation, unless there are charges against them, the spokeswoman, Nada Doumani, told Associated Press Television News.

However, the chief Red Cross spokeswoman, Antonella Notari, later clarified those remarks by noting that while the Red Cross has said POWs are entitled to immediate freedom at the end of a war or occupation, "nobody in the ICRC is calling for the release of Saddam Hussein. Absolutely not."

The former dictator has been in U.S. custody in an undisclosed location since he was found in December hiding in a tiny underground bunker.