A suicide bomber wearing a vest packed with explosives killed up to 40 people in a Baghdad college Sunday, a day after Prime Minister Nuri al-Maliki expressed optimism about a security crackdown in the capital.

Guards stopped the bomber in the reception lobby of the Baghdad Economy and Administration College but the man managed to blow himself up, police said.

One senior police official put the death toll at 40, with 35 people wounded. Another police source said 22 people had died. Most of the victims were students, witnesses said.

"May God curse the terrorists," shouted some students after the attack. Others sat on the ground outside weeping.

A string of car bombings and rocket salvos also hit Baghdad Sunday as insurgents defied efforts by US and Iraqi security forces to stabilize the capital.

A professor said the attack happened as students were leaving morning classes and arriving for afternoon lessons. Others doing exams were wounded by flying glass that tore through their classroom, the professor said.

"There were bodies everywhere," said the professor, who declined to be identified.

The blast left large pools of blood in the college's reception area. Textbooks and pens lay scattered on the floor.

The college is part of nearby Mustansiriya University, which was hit by twin bomb attacks last month that killed 70 people, mainly students.

Insurgents have repeatedly attacked universities and colleges in Baghdad, trying to strike fear into the city's middle class. Many college professors and intellectuals have also been killed.

In a bold challenge to the security crackdown in Baghdad, regarded as a last chance to reverse Iraq's descent into civil war, gunmen stormed a police checkpoint near Baghdad airport on Saturday, killing eight policemen.

Maliki expressed optimism on Saturday about the 10-day-old security plan and said US and Iraqi forces had killed about 400 suspected militants since it began.

US military officers have said they expected an increase in the use of suicide vests after security forces set up more checkpoints on Baghdad's roads to search vehicles and try to prevent car bombs.

Among the attacks Sunday, rockets and mortar bombs crashed into a market in a Shi'ite area in southern Baghdad. One police source said 10 people were killed in the attack in the Abu Dsher area of Doura neighborhood.

(China Daily via agencies February 26, 2007)