QUETTA: Gunmen attacked a police post in Pakistan's insurgency-hit southwestern Balochistan province, an official said Sunday, killing two constables. 

No one immediately claimed responsibility for the attack, but Baloch separatist groups, who want independence from Pakistan, have been active in the mineral- and gas-rich province that borders Iran and Afghanistan. 

"The gunmen fled on motorcycles after shooting the police officers at the Mundrani security post near the town of Dera Murad Jamali," AP news agency quoted police officer Aziz Jamali as saying. 

Balochistan, Pakistan's largest province in terms of land area, has long been marred by a low-level insurgency and sectarian attacks. Militants often target security forces, law enforcement and non-natives they accuse of taking jobs in the province. 

Late Friday, three laborers were killed and five wounded in a militant attack on a road construction camp in the Harnai district. 

The assailants opened fire on the camp, burned vehicles and destroyed machinery in a mountainous part of the district, said Farah Azeem Shah, a spokesperson for the Balochistan provincial government.  

Five workers were missing from the camp after the attack, said Rafiq Tareen, district deputy commissioner. Later, he said two of them were found nearby.