At least seven people including four policemen were killed in a suicide attack near the Balochistan Assembly building in Quetta on Tuesday, local officials confirmed.

The officials said 21 people including seven policemen were wounded in the blast.

The attack took place after a suicide bomber detonated his explosives close to a police truck near GPO Chowk in Quetta. 

The police personnel were returning after completing routine duty when the bomber detonated his explosives near their vehicle. The blast also damaged a nearby public bus, Pakistan’s GEO news reported.

Initial investigations suggested that the suicide attacker was attempting to reach the Balochistan Assembly building but detonated his explosives near the police vehicle close to the high-security zone, the report said.

No group has so far claimed responsibility for the blast.