BAGHDAD — Another wave of bombings tore through Baghdad on Monday, killing at least 55 people. It was the latest of a series of well-coordinated attacks blamed on hard-line Sunni insurgents determined to rekindle large-scale sectarian conflict.
Most of the blasts on Monday were caused by car bombs detonated in Shi'ite neighborhoods.
Multiple coordinated bombing strikes have hit Baghdad repeatedly over the last five months. On Sunday, a series of bombings in different parts of Iraq, including two suicide bombings in the country's relatively peaceful northern Kurdish region, killed 46 people.
The Shi'ite-led government has announced new security measures, conducted counter-insurgency sweeps of areas believed to hold insurgent hideouts, and sponsored political reconciliation talks, but it has not significantly slowed the pace of the bombing campaign.
No group immediately claimed responsibility for the bombings, but they bore the hallmarks of Al Qaeda's local branch in Iraq, known as the Islamic State of Iraq.
Al Qaeda is believed to be trying to build on the Sunni minority's discontent toward what they consider to be second-class treatment by the government and on infighting among political groups.
In addition to helping Al Qaeda gain recruits, the political crisis may also be affecting the security forces' ability to get intelligence from Sunni communities.
''Our war with terrorism goes on,'' said Saad Mann, a spokesman for the Interior Ministry. "Part of the problem is the political infighting and regional conflicts. . . . There are shortcomings and we need to develop our capabilities mainly in the intelligence-gathering efforts.''
The deadliest of Monday's bombings was in the eastern Sadr City district, where a parked car bomb tore through a small vegetable market and its parking lot, killing seven people and wounding 16, a police officer said.
Other parked car bombs went off in quick succession in the Shi'ite neighborhoods of New Baghdad, Habibiya, Sabaa al-Bour, Kazimiyah, Shaab, Ur, Shula as well as the Sunni neighborhoods of Jamiaa and Ghazaliyah. Police officers said 44 people were killed and 139 wounded.
And in the evening, a roadside bomb outside a Sunni mosque within a refinery compound in the south Baghdad district of Dora killed four and wounded 14. Some such attacks on Sunni targets are blamed on hard-line militants targeting rival Sunnis, but there are also indications that Shi'ite groups have started to retaliate, raising fears of a return to the widespread sectarian killing of 2006-2007.
Medical officials confirmed the casualty figures in Monday's attacks. All officials spoke on condition of anonymity because they were not authorized to talk to the media.
Iraqi security forces sealed off the sites of the attacks as firefighters struggled to extinguish fires that broke out. The twisted wreckage of cars and remnants of the car bombs littered the pavement.
Iraqi militants often target crowded places such as markets, cafes and mosques, seeking to inflict huge numbers of casualties.
Monday's attacks were the biggest since the Sept. 21 suicide bombings that struck a cluster of funeral tents packed with mourning families in Sadr City, killing at least 104 people.
More than 4,500 people have been killed since April. Although overall death tolls are still lower than at the height of the conflict, the cycle of violence is reminiscent of the one that brought Iraq to the brink of civil war.
On Sunday, several bombs exploded in the heart of the Kurdish region of northern Iraq, setting off gunfights in the streets of Irbil, the capital of the region.
The attacks came just after the results of the region's parliamentary elections were announced, but much of the speculation about the motivation for the attack centered on Syria, where Kurdish militias, some of them supported and trained by the security forces in Iraqi Kurdistan, have been fighting against jihadist groups linked to Al Qaeda. No group immediately claimed responsibility for the bombings.
Twin suicide car bombs killed at least six Kurdish troops and wounded 30 others in a rare attack in Irbil, the capital of Iraq's self-ruled northern Kurdish region.
The first blast targeted a checkpoint leading to a downtown complex housing the Interior Ministry and other security agencies.
As rescue crews and bystanders gathered at the scene, another bomber driving an ambulance attacked the area, said Nawzad Hadi, the governor of the surrounding province of the same name. Gunmen then tried to storm the area, prompting a gunfight with security forces that left at least three attackers dead, he added.