A series of car bombs targeting markets and shopping streets in and around Baghdad killed at least 35 people.
Over 90 people were wounded in the attacks.
Security has been increased in the capital this week by closing roads and deploying additional police and helicopters.
Six separate car bombs went off in eastern and southern districts of the capital in quick succession.
One of the attacks hit a square in central Baghdad, where a parked car bomb killed five and wounded 18.
In Nahrawan, 30km southeast of Baghdad, militants targeted a crowded commercial street with a car bomb.
The Interior Ministry has said Iraq was facing an "open war" fuelled by sectarian violence.