In Tarmiya, which is predominantly Sunni, a man detonated a suicide vest at a checkpoint, killing three soldiers and wounded seven others, CNN reported.
Five people died and 43 others were wounded when a car bomb exploded in a Shiite Turkmen neighborhood in Tuz Khurmato, police said.
In the ethnically mixed city of Kirkuk, three roadside bombs at a cattle market killed six people and wounded 25 others, officials said.
The latest attacks occurred amid an increase of Sunni-Shiite violence in Iraq during recent weeks.
Martin Bashir resigns from MSNBC over Sarah Palin comments
Exploding whale video goes viral on Internet