According to a report in the Dawn, the workers were part of a team working on a major highway in the Hoshab area of Turbat, linking the port-city of Gwadar to Quetta.
"The labourers belonged to the Khairpur area of the Sindh province," said Sarmad Saleem, a regional official.
The three men were making a trip to the marketplace to buy daily supplies when they were shot.
The assailants managed to flee on a motorcycle.
The incident comes almost a week after the miscreants killed 10 labourers in Pishgan area of Gwadar district.
Security officials have said previously that militants trying to disrupt construction on the economic corridor have killed 44 workers since 2014, all of whom were Pakistani.
The Pakistan military created an army division in 2015, believed to number more than 10,000 troops, specifically to protect the CPEC projects and Chinese workers. (ANI)