Iraqi officials say a suicide car bomber has killed six troops and Shiite militiamen in a flashpoint area north of Baghdad that has seen much fighting with Islamic State militants.

Police officials say the bomber drove his explosive-laden car into a checkpoint jointly manned by the Shiite militia and Iraqi army near Samarra, 60 miles from Baghdad.

Hospital officials say four militiamen and two soldiers were killed and at least 16 people were wounded. All officials spoke on condition of anonymity because they were not authorized to talk to the media.

No one immediately claimed responsibility for the explosion but Samarra and the surrounding areas have been under constant attacks by the Islamic State group, which captured large swaths of western and northern Iraq last summer.