BAGHDAD (AP) – Iraqi police say a roadside bomb has killed at least three people near the northern city of Kirkuk.

The victims are civilians who were traveling about 20 miles (32 kilometers) south of the ethnically mixed city. Police Brig. Gen. Sarhad Qadir says the blast hit a car and cement mixer. It is not known whether the vehicles were the intended targets of the blast.

Oil-rich Kirkuk has been the scene of rising tensions linked to a power struggle between the majority Kurds and Arabs. But other groups have been hit by violence. Last Sunday, gunmen killed three Christians in the city, about 180 miles (290 kilometers) north of Baghdad.