BAGHDAD, Iraq - Twin car bombs tore through a leading Baghdad university as students left classes Tuesday in the deadliest attack in Iraq in nearly two months, and the United Nations reported 34,452 civilians were slain last year, nearly three times more than the government reported.

The wreckage of vehicles lies on a road after a car bomb attack near a university in Baghdad January 16, 2007. A car bomb near a university in eastern Baghdad killed 10 people and wounded 25 more on Tuesday, an Interior Ministry source said, adding that the toll may rise. [Reuters]

A total of 142 Iraqis were killed or found dead Tuesday, in what appeared to be a renewed campaign of Sunni insurgent violence against Shiite targets. The sharp uptick in deadly attacks coincided with the release of UN figures that showed an average of 94 civilians died each day in sectarian bloodshed in 2006.

The blasts wrecked two small buses as students at Al-Mustansiriya University were lining up for the ride home at about 3:45 p.m., according to Taqi al-Moussawi, a university dean. The attackers stationed a man wearing a suicide belt in the expected path of fleeing students to take even more lives, but he was spotted and shot by security men before he could blow himself up, the dean said.

"The only guilt of our martyred students is that they pursued education. They belong to all religions, sects and ethnic groups," said an angry al-Moussawi, himself a Shiite. "The terrorists want to stop education. ...Those students had nothing to do with politics."

After the explosions, a rescue worker and three men in civilian clothes scrambled through the debris to carry a charred victim away in a sheet. Firefighters in yellow helmets examined the charred wreckage of an bashed-in, overturned minivan.

The university's well-shaded campus occupies several square blocks in north central Baghdad, a mostly Shiite area. The school ranks second among institutions of higher education in Iraq. Founded in 1963, it was named after one of the oldest Islamic schools, established in the 13th century during the Abbasid dynasty that ruled the Muslim world. Thousands attend the university, known especially for its colleges of science, literature and education.

Prime Minister Nouri al-Maliki blamed the attack on "terrorists and Saddamists" seeking revenge for Monday's hanging of two of Saddam Hussein's top aides, convicted with him for the slaying of 148 Shiite men and boys after a 1982 assassination attempt in the northern town of Dujail.

The violence Tuesday against Shiites may signal a campaign by Sunni insurgents to shed as much blood as possible before the deployment of 21,500 more American troops. Most of the additional U.S. troops will be used to back up the Iraqi army in a security sweep to rid the capital of Sunni and Shiite gunmen.

Secretary of State Condoleezza Rice, in Kuwait for a meeting with eight Arab nations to discuss ways to keep Iraq from sliding into civil war, sought to lower any expectations that the troop buildup would quickly pacify the country.

"Violent people will always be able to kill innocent people," she said. "So even with the new security plan, with the will and capability of the Iraqi government and with American forces to help reinforce Iraqi forces, there is still going to be violence."

She said the UN civilian death figures differ from others. "But whatever the number of civilians who have died in Iraq ¡ª and there obviously are competing numbers ¡ª but whatever the number is, it's too many," she said.

The university bombing's death toll was the highest daily toll since suspected al-Qaida in Iraq fighters staged a series of car bombs and mortar attacks on Baghdad's Sadr City Shiite slum. That attack killed at least 213 people on Nov. 23.

The UN civilian casualty count for last year was announced in Baghdad by Gianni Magazzeni, the chief of the UN Assistance Mission for Iraq in Baghdad. He said 34,452 civilians died ¡ª an average of 94 a day ¡ª and 36,685 were wounded.

But Dr. Hakem al-Zamili, Iraq's deputy health minister, told The Associated Press the United Nations may be using unreliable sources for its casualty count. "They might be taking the figures from people who are opposed to the government or to the Americans," he said. "They are not accurate." He said he would provide Iraqi government figures later this week.

In early January, a compilation of Iraqi government figures put last year's civilian deaths at just 12,357. The numbers are gathered monthly by the AP from reports by three Iraqi agencies.

When asked about the difference, Magazzeni said the UN figures were compiled from information obtained through the Iraqi Health Ministry, hospitals across the country and the Medico-Legal Institute in Baghdad.

He criticized the government for allowing much of the violence to go unpunished, saying urgent action was needed to re-establish law and order in the country to prevent its slide into all-out civil war.

"Without significant progress in the rule of law, sectarian violence will continue indefinitely and eventually spiral out of control," he warned.

The UN report also said that 30,842 people were detained in the country as of Dec. 31, including 14,534 held in U.S. military-run prisons.

At least 470,094 people throughout Iraq have been forced to leave their homes since the bombing of an important Shiite shrine, the Golden Dome mosque in Samarra, in February, the UN accounting said.

The report said the violence has disrupted education by forcing schools and universities to close, as well as sending professionals fleeing from the country.

In a summary of the report posted on its Web site Tuesday, UNAMI said Iraq's women were particularly vulnerable, citing cases where young women were abducted by armed militia and late discovered sexually assaulted, tortured or murdered. In many cases, the agency said, families refuse to retrieve the bodies out of shame.

As bombs detonated at Al-Mustansiriya University on Tuesday, there were a series of other attacks on Shiite neighborhoods in central Baghdad.

A bomb planted on a motorcycle exploded in a used auto and motorcycle parts market in a Shiite neighborhood. As people rushed to aide the victims of the first blast, a suicide car bomber drove his car into the crowd. Fifteen people died.

Raid Abbas, a 26-year-old who received shrapnel wounds in the attack said he went to the market because the city had been quieter over the past two weeks.

"Shortly after midday, I heard an explosion. Motorcycles were flying in the air, people were falling dead and wounded," he said from his hospital bed.

About 45 minutes later, gunmen riding two motorcycles and in a van fired on another outdoor market in a mainly Shiite neighborhood near Sadr City. Police said at least 11 people were killed.

Of the 142 Iraqis killed or found dead Tuesday, 124 died in Baghdad. Police said they had been unable to complete their tally of dumped corpses in the eastern half of the city because of violence there.