BAGHDAD — Bombs and deadly shootings relentlessly pounded Iraqis on Thursday, killing at least 55 people and wounding more than 225 in a widespread wave of violence the government called a “frantic attempt” by insurgents to prove the country will never be stable.

Cars burned, school desks were bloodied, bandaged victims lay in hospitals and pools of blood were left with the wounded on floors of bombed businesses after the daylong series of attacks in 12 cities across Iraq.

The assault demonstrated how vulnerable the country remains two months after the American military left and put the onus for protecting the public solely in the hands of Iraqi forces.

“There was no reason for this bomb. A primary school is here, students came to study and people came to work,” Karim Abbas woefully said in the town of Musayyib, where he saw a car bomb parked near an elementary school kill three people and wound 73. Most of the injured in the town, 40 miles south of Baghdad, were schoolchildren.

Other Iraqis, fed up with the continued violence, furiously blamed security forces for letting it happen.

“We want to know: What were the thousands of policemen and soldiers in Baghdad doing today while the terrorists were roaming the city and spreading violence?” said Ahmed al-Tamimi, who witnessed an explosion that killed nine people.

No group immediately claimed responsibility for the latest attacks, but car bombs are a hallmark of al-Qaida. The Iraqi Interior Ministry blamed al-Qaida.

Printed on Friday, February 24, 2012 as: Baghdad erupts in violence, security worsens