Four Sindhi labourers were gunned down by suspected militants in Balochistan's Kharan district on Wednesday, police sources said.
The labourers were working on construction of a road in the district ─ a project which falls under the National Highway Authority ─ when the suspected militants opened fire on them, the sources said.
The assailants escaped unhurt from the site of the attack.
Police and Levies personnel arrived on location as an investigation into the attack went underway.
Levies forces termed the incident an act of target killing as all the victims belonged to Sindh.
The bodies were transported to District Headquarters Hospital Kharan.
There was no immediate claim of responsibility for the attack.
Suspected separatist elements in Balochistan often target non-native labourers working on development projects in the province.
In April, 2015, 20 labourers were killed while working for a private construction company in Gokdan, about 15 kilometres from Turbat city in Balochistan.
Most of the victims hailed from Sindh and Punjab who were busy working on an under-construction bridge over the Sorap stream. The responsibility of the killings was claimed by the Balochistan Liberation Front (BLF).