Suspected militants on Friday gunned down three workers building a Chinese-funded "Silk Road" highway in Balochistan, just days after a similar attack killed 10 labourers, officials said.

The men killed on Friday were part of a team working on a major highway in the Hoshab area of Turbat, linking the port-city of Gwadar to Quetta, said Sarmad Saleem, a regional official.

"One laborer died on the spot and two others succumbed to their injuries in hospital," Saleem said.

They were making a trip to a marketplace in the small town of Hoshab, 280 km from Gwadar, to buy daily supplies, said an official of the paramilitary force overseeing security in Baluchistan.

The assailants managed to flee on a motorcycle.

Levies and frontier corps personnel reached the spot to initiate an investigation into the incident.

The officer said the labourers had been working on the construction of a road under the Frontier Works Organization (FWO). "The labourers belonged to the Khairpur area of Sindh province," he said.

The incident comes almost a week after the miscreants killed 10 labourers in Pishgan area of Gwadar district.