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.

The daylong series of attacks hit 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, located about 40 miles south of Baghdad, were schoolchildren.

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