Unknown assailants targeted the vehicle with a hand grenade which resulted in the explosion, killing one policeman and two bystanders.
Meanwhile, Quetta’s police chief Hamid Shakeel said the nature of the explosive device was under investigation. The blast also destroyed the police van carrying the officers.
No group immediately claimed responsibility. But Balochistan province, of which Quetta is the capital, has long been the scene of a low-level insurgency which aims to win more autonomy for the province and a greater share of the money from its natural resources.