Five car bombs hit Baghdad on Wednesday morning, killing at least nine people, Iraqi police and medical sources said.
Most of the bombs targeted Shiite-majority areas of the Iraqi capital.
It is the latest in a wave of increased nationwide violence that has sparked concern that Iraq is teetering on the edge of a return to the brutal all-out sectarian war that left tens of thousands dead in 2006 and 2007.
Security forces have carried out wide-ranging operations in recent weeks in a bid to combat the unrest, arresting hundreds of alleged militants and killing dozens of others.
Prime Minister Nuri al-Maliki has vowed to press on with the anti-insurgent campaign, but analysts say the government should focus on resolving anger in the Sunni Arab community over perceived ill-treatment by the Shiite-led authorities and security forces.