Near the main northern city of Mosul, a car bomb exploded as security forces searched a home, killing three policemen and wounding 15 people, police and medical sources said.
Gunmen killed a fourth policemen inside the city.
And in north Baghdad, gunmen opened fire on a group of civilians, killing three and wounding one.
Iraq is struggling to contain a wave of violence that has killed more than 430 people so far this month -- the second month in a row in which more than 400 people have died in unrest.