Updated

A suicide driver rammed his explosive-laden car into a police checkpoint at the entrance to Baghdad's Khazimiyah district killing 21 people, including seven policemen manning the post.

Police officials say there was a long line of cars at the checkpoint at the time of the attack. At least 35 people were wounded, according to police and hospital officials.

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

Baghdad has been on edge since the Sunni militant blitz led by the Islamic State extremist group seized the northern city of Mosul, vowing to push south to the capital. The city has seen several small scale bombings in recent weeks, but it has so far been free of the large, coordinated attacks.