Authorities in Iraq say coordinated suicide attacks targeting security posts have killed 10 people north of Baghdad.

Police officials say four suicide bombers driving explosive-laden cars rammed into two security checkpoints and a military headquarters in the al-Hajaj area on Saturday, killing 10 Shiite militiamen and troops. They say at least 20 people were wounded.

Al-Hajaj lies on the road between Beiji and Tikrit in Salahuddin province.

Police said the four suicide attacks took place within a 15-minute period.

Hospital officials confirmed the casualty figures. All officials spoke on condition of anonymity as they weren't authorized to speak to journalists.

Iraqi forces, backed by Shiite militias, have been struggling to regain control of vast areas lost to the Islamic State group during its stunning blitz last year.