As the car bombers struck, US forces kept up operations against rebel-held towns elsewhere aimed at establishing control throughout the country ahead of January elections. Air strikes were launched against suspected militants in Falluja.

In the first blast in western Baghdad, a car blew up near one of the entrances to the heavily fortified Green Zone, close to an Iraqi security forces recruitment post, killing at least 15 people and wounding 80, an official at Yarmouk hospital said.

No US troops were killed or wounded, a spokesman said.

A second bomb exploded about an hour later as a US military convoy was passing along Baghdad's Sadoun Street, a major thoroughfare on the eastern side of the Tigris river, where several hotels used by foreign contractors are located.

Witnesses said a small truck charged toward a group of four-wheel-drive vehicles and detonated, destroying half a dozen cars, shattering scores of shop windows and spraying wreckage across the street. At least six people were killed and more than a dozen wounded, a source at Iraq's Interior Ministry said.

"I saw a head in one place and a leg in another. This was a suicide bombing," said one bystander as thick clouds of black smoke billowed behind him and US helicopters circled overhead.

The US military said no soldiers were killed or wounded.

In a third attack, a car bomb exploded outside a primary school in the northern city of Mosul, killing five people, including two children, police said. Earlier police had said seven were killed, but later revised the toll. Eleven people were wounded, including five children.

The car, driven by two men, may have exploded prematurely, a US officer at the scene said, as there was no obvious target in the area, a quiet district in the south of the city.

Operations to restore government control continued in Samarra, a city north of Baghdad that US and Iraqi forces overran on Friday.

In a 36-hour blitz, some 3,000 US troops and 2,000 Iraqi soldiers, backed by US warplanes and artillery, stormed the city, 60 miles north of Baghdad, in an effort to dislodge an estimated 500 to 1,000 guerrillas.

US forces said they killed 125 fighters and captured 88 in the assault, which destroyed dozens of buildings and, according to locals, inflicted a heavy toll on civilians.

Residents of Samarra tried to bury their dead yesterday -- the cemetery was off limits on Sunday -- progressing through the streets of the city waving sticks with white flags attached, family members weeping as they bore the coffins for burial.

Iraq's interior minister, who comes from Samarra, said he did not believe any civilians had been killed in the offensive, a statement which drew an angry response from residents. The US military said it had tried to avoid civilian casualties.

Aid agencies returned to the city on Sunday, delivering food, water and medicine to families forced to flee. Much of the city still lacked water and electricity on Monday.

The two biggest challenges facing US and Iraqi forces are Falluja and Ramadi, guerrilla strongholds west of Baghdad which the US military tried unsuccessfully to capture in April.

There are also areas of Baghdad, including the Shia slum district of Sadr City, that will have to be seized from rebels.

In rebel-held Fallujah, American warplanes unleashed strikes on two houses early yesterday, killing at least 11 people, including women and children, hospital officials said.

The military, which regularly accuses hospitals of inflating casualty figures, said the strikes targeted followers of Jordanian terror mastermind Abu Musab al-Zarqawi and their associates.

A strike in the central al-Jumhuriyah area killed nine people, including three women and four children, said Dr. Adil Khamis of Fallujah General Hospital. Twelve were injured, including six women and three children, he said. They include residents of neighboring houses that were damaged in the blast.

A second strike in the city's southern Al-Shuhada neighborhood killed two more people, Khamis said.

The military said a "precision strike" at about 1 a.m. hit a building where about 25 insurgents were moving weapons on the outskirts of Fallujah.

Intelligence sources said insurgents were using the site to store weapons and conduct training, the military said in a statement.

"Throughout the operation, multiple measures were employed to ensure no innocent civilians were present when the strikes took place," the statement said.

Shortly before 3:30 a.m. coalition forces struck a site where members of al-Zarqawi's network were believed to be meeting, another military statement said.

It was the latest in weeks of strikes in the city west of Baghdad aimed at groups with links to terrorists, particularly al-Zarqawi's network. Followers of the Jordanian militant have claimed responsibility for a string of deadly bombings, kidnappings and other attacks across the country.

Yesterday's violence comes a day after Iraqi security forces emerged to patrol Samarra following a morale-boosting victory in this Sunni Triangle city of Samarra.

American and Iraqi commanders have declared the operation in Samarra, 60 miles northwest of Baghdad, a successful first step in a major push to wrest key areas of Iraq from insurgents before January elections.

Also in Baghdad, a senior official of Iraq's Sciences and Technology Ministry and a female employee were assassinated Monday, the Interior Ministry said. Thamir Abdul-Latif and the woman were killed near Baghdad's southeastern Zayona suburb, said Col. Adnan Abdul-Rahman.