BAGHDAD — Iraqi security officials say a suicide car bomber killed 13 troops and allied Sunni militiamen near the insurgent-held capital of the western Anbar province.

The officials say the suicide bomber used an army vehicle to approach forces advancing southeast of Ramadi, west of Baghdad, on Tuesday. They say seven people were wounded in the attack.

The officials spoke on condition of anonymity because they were not authorized to speak to the media.

There was no immediate claim of responsibility for the attack, but it bore the hallmarks of the Islamic State group, which controls Ramadi and much of the vast Sunni province.

Troops and allied militias have been battling IS militants for months in Anbar but have not been able to dislodge them from areas under their control.