While no one claimed responsibility for the attack, the province has seen an increase in strikes by separatist ethnic militants. This month, 21 miners working at privately run coal mines were killed in an attack, Reuters reported.
A decades-long insurgency in Balochistan by separatist militant groups has led to frequent attacks against the government, army, and Chinese interests in the region to press their demands for a share in mineral-rich regional resources.
China runs a strategic deepwater port as well as a gold and copper mine in the province and has been working with Islamabad to improve infrastructure in the underdeveloped province. Several attacks have targeted migrant workers employed by smaller, privately operated mines.
The five dead, and two injured, all worked at the construction site in the Panjgur, spokesperson for the Balochistan government Shahid Rind said in a statement, saying the attack took place late at night.
A police official, speaking on anonymity, said close to a dozen assailants were involved in the attack and that the victims were watching over equipment at the site dam construction site on behalf of a private contractor.
"Such cowardly attacks will not deter the government's resolve to develop Balochistan," Prime Minister Shehbaz Sharif said in a statement.
SD/