The victims were identified as Mohammad Bilal, Mohammad Hussain, Mohammad Qadeer, Mohsin and Bilal, the sources added.
The sources further said that the security forces, meanwhile, cordoned off the area and launched a search operation to track down the terrorists in Mashkel, Washuk district.
Police said all five victims had travelled from outside the province, adding that the bodies were being shifted to their native areas after completion of legal formalities.
According to police, an investigation into the incident had been launched.
Balochistan Chief Minister Sarfraz Bugti condemned the killing of the unarmed labourers, saying terrorists had once again exposed their "sinister intentions" by targeting innocent workers.
"The objective of terrorists is not the pursuit of any cause but to spread terror, hatred and destabilise Pakistan," CM Bugti said, adding that action against those challenging the writ of the state would become "more decisive".
Balochistan government spokesperson Shahid Rind also condemned the incident, saying the provincial government had taken notice of the attack and ordered an investigation.
"Those involved in the killing of innocent citizens will not escape the grip of the law," Rind said, adding that the government stood with the bereaved families in their time of grief.
PM condemns 'cowardly act'
Prime Minister Shehbaz Sharif condemned the killing of the labourers by terrorists, saying those involved in such crimes against humanity deserved no leniency.
The prime minister expressed condolences and sympathies to the families of the victims, describing the targeting of labourers as an "extremely barbaric and cowardly act".
"No condemnation is enough for this cowardly act," the prime minister said, adding Fitna al-Hindustan terrorists were targeting innocent civilians to pursue their "nefarious designs".
However, he said that such cowardly attacks can never weaken the nation's resolve against terrorism.
PM Shehbaz resolved that the government and security forces remained fully committed to eliminating terrorism and ensuring the protection of citizens' lives and property.
The incident comes amid ongoing security operations across the province, during which dozens of India-backed terrorists have been killed.
Security forces launched Operation Shaban following the attack on the Mangi Dam police station in Ziarat. The operation is being conducted jointly by the Pakistan Army, Frontier Corps (FC), and Balochistan Police, sources had said earlier.
Pakistan witnessed a surge in terror activities, particularly in its Khyber Pakhtunkhwa and Balochistan provinces, since 2021, when the Afghan Taliban came into power.
In response, Pakistan launched Operation Ghazab lil-Haq, targeting terrorist hideouts across the border.
Despite several rounds of talks, both countries have been unable to reach an agreement, largely due to the Afghan Taliban regime’s reluctance to take action against terrorist outfits.