Iraqi officials say bombings and other attacks have killed at least 23 people in mainly Shi'ite areas of the capital, Baghdad.
The violence Tuesday also wounded 80 others, a day before the 10th anniversary of the U.S.-led invasion.
There was no immediate claim of responsibility for the attacks.
Sunni Muslim militants in Iraq frequently attack the country's majority Shi'ites to inflame sectarian tensions and undermine the Shi'ite-led government.