QUETTA/Okara - Six labourers belonging to Okara were killed and another sustained injuries when some unidentified armed men opened firing on them in Balochistan’s Kharan on Friday, in the latest bout of violence to rock the province.

According to Levies force personnel, the victims belonging to Punjab’s Okara city were hired by a private mobile phone company for work at a tower.

The murders took place overnight in Lajjey area of Kharan, about 170 kilometres southwest of Quetta.

"Unidentified gunmen shot dead six labourers and wounded another, who is in critical condition," local government official Hashim Ghilzai told AFP.

The labourers were working on a mobile tower and were sleeping in tents at the site when the gunmen attacked, Ghilzai said, adding that "it appeared to be an act of terror".

Local security official Tariqur Rehman confirmed the incident and casualties.

The bodies were shifted to a hospital whereas investigation into the incident was launched. Back in Okara, families of the six slain labourers learnt the news of their death through social media.

The victims were identified as Waqas, Shahzad, Mazhar and Farhan Rafiq of village 49/2L and two young men belonged to village Theekrywala.

According to the six families, the young labourers had left for Balochistan just two days ago.

Deceased Mazhar had been married for years ago and had two daughters. The dead bodies of the six young labourers were awaited at their homes for burial.

No group has claimed responsibility for the killings, but Balochistan is home to a long-running ethnic insurgency aimed at seeking greater control over the province's abundant mineral resources.

Militants have previously targeted ethnic Punjabi and Sindhi labourers, who are largely considered outsiders in many parts of the province and viewed with deep suspicion.

In the recent past, gunmen killed 20 construction workers in Balochistan, shooting them at point blank range after identifying they were not local.

Hundreds of soldiers and militants have been killed since the insurgency flared up in the mid-2000s. Pakistan also regularly accuses its eastern neighbour India of funding and arming the insurgents.