QUETTA: Four labourers involved in road construction were killed by unk**wn gunmen in the Yakmach area of Kharan district on Thursday.According to Levies sources, all the victims were residents of Sindh and were constructing a road in the Yakmach area when some armed assailants riding motorbikes came there and opened fire at them and fled from the spot.As a result, they died on the spot after receiving bullet wounds. The bodies were rushed to a nearby hospital where the victims were identified as Ghulam Mustafa, Sajad, Niazi and Surab Khan.Local administration cordoned off the entire area and started efforts to arrest the suspects.