Ten car-bomb explosions killed at least 39 people across the Iraqi capital on Monday, police and medical sources said.
In the central district of Karada, two parked car bombs went off killing at least eight people, and another two car bombs exploded simultaneously near a market in the western district of Jihad, killing eight.
Violence has been increasing in Iraq in recent months, with more than 1,000 people killed in May alone, making it the deadliest month since the sectarian bloodletting of 2006-07.
Insurgents including al-Qaida's Iraqi affiliate have been regaining ground and recruits from the country's Sunni minority, which feels sidelined since the U.S.-led invasion toppled former dictator Saddam Hussein and empowered majority Shi'ites.
Sectarian tensions in Iraq and the wider region have been inflamed by the civil war in Syria, where mainly Sunni Muslim rebels are fighting to overthrow President Bashar al-Assad, whose Alawite sect derives from Shi'ite Islam.