Four car bomb blasts killed at least 18 people on Friday in two mainly Shiite Muslim areas of central Iraq, police sources said, dpa reported.
Thirteen were killed and 26 injured in central Baghdad's Kadhimiya area. A parked car went off first, followed by another in the middle of a bird market in the neighbourhood.
In Hilla, 100 kilometres south of Baghdad, five people were killed and 12 injured when two car bombs exploded consecutively.
The blasts come amid a widening crisis in Iraq between the Shiite-led government and the country's formerly dominant Sunni minority.
Thousands of Sunni protesters have been rallying for weeks against Shiite Prime Minister Nuri al-Maliki, demanding a repeal of laws they claim target Sunnis.