Iraqi officials said extremists launched 12 attacks in the capital and in the cities of Kirkuk, Samarra, Baqouba, Dibis and Taji, sparking the first deadly attacks in nearly a month.
Half of the bombs struck at security forces and government officials - two frequent targets for insurgents still seeking to undermine Iraq's efforts to normalize after years of war and violence.
An Iraqi military spokesman said there was no immediate claim of responsibility, but the attacks resemble those carried out by al Qaeda.
The Associated Press contributed to this report.
