BAGHDAD — A coordinated wave of car bombings tore through mostly Shiite areas of Baghdad on Monday, killing at least 66 people and maiming nearly 200 as insurgents step up the bloodshed roiling Iraq.
The attacks in markets and other areas frequented by civilians are the latest sign of a rapid deterioration in security as sectarian tensions are exacerbated by antigovernment protests and the war in neighboring Syria grinds on. More than 450 people have been killed across Iraq in May. Most of the killings came over the past two weeks in the most sustained wave of violence since U.S. troops left in December 2011.
The surge in attacks is reminiscent of the sectarian carnage that pushed Iraq to the brink of civil war in 2006 and 2007. April was Iraq's deadliest month since June 2008, according to a United Nations tally that put last month's death toll at more than 700.
There was no claim of responsibility for Monday's bombings, but they bore the hallmarks of al-Qaida's Iraqi arm. The group, known as the Islamic State of Iraq, frequently uses car bombs and coordinated blasts against Shiites to undermine Iraqis' confidence in the Shiite-led government.
The day's deadliest attack happened when two bombs exploded in the eastern Habibiya area on the edge of the sprawling Shiite district of Sadr City. Those blasts killed 12 and wounded 35, police said.
Twin blasts also struck an open-air market in the predominantly Shiite al-Maalif area, killing six and wounding 12.
Another car bomb exploded in the busy commercial Sadoun Street in downtown Baghdad. It killed five civilians and wounded 14, police said. Among the wounded were four policemen who were at a nearby checkpoint. The central street is lined with clinics, pharmacies and shops. Firefighters were seen struggling to extinguish flames as police sealed off the area. Several shops were damaged or burned.
''What crime have those innocent people committed?" asked witness Zein al-Abidin. "Who is responsible for these massacres?"
Medical officials confirmed the causality figures. All officials spoke to the Associated Press on condition of anonymity because they were not authorized to release information.
The day's bloodshed was the deadliest since May 20, when a wave of attacks killed 113 people in Shiite and Sunni areas.