No group immediately claimed responsibility for the attack but Baluch separatists demanding greater autonomy have been waging an insurgency for years while the province is also riven by sectarian strife and Islamist violence.

Interior minister Ejaz Shah said in a statement that “such attacks are aimed at spreading fear among the people”.

Mineral-rich Balochistan, bordering Afghanistan and Iran, is the largest of Pakistan’s four provinces, but its roughly seven million inhabitants have long complained they do not receive a fair share of its gas and mineral wealth.

China is investing in the area under a $54 billion project known as the China-Pakistan Economic Corridor, upgrading infrastructure, power and transport links between its far-western Xinjiang region and Pakistan’s Gwadar port in Balochistan.

Thousands of paramilitary troops carry out security checks and help police in maintaining law and order in restive parts of Pakistan.