At least 20 workers at a dam construction site in Pakistan’s southwestern province of Balochistan were killed by militants early on Saturday, according to local media reports. Although no group has so far claimed responsibility for the attack, Taliban and several Baloch separatist groups are believed to be active in the region.

“The laborers were working on construction of a small local bridge,” Tariq Khilji, a senior police official in the Gogdan area of Balochistan, reportedly said, adding that the militants lined up the workers and then “shot them at point blank range.”

Imran Qureshi, another police official in the region, told Pakistani newspaper Dawn, that most of those killed were from the Sindh province in the east. And, because the guards, who are from Balochistan, were left unharmed, the needle of suspicion pointed toward separatist groups who have, in the past, targeted non-Baloch settlers.

Sarfaraz Bugti, the home minister of Balochistan, said the country’s security forces were searching the nearby mountains for the attackers. “We will chase them down and bring them to justice,” Bugti said, according to media reports.

Militant and rebel groups in the region have also attacked members of the Hazara minority in the province. According to a Human Rights Watch report released last year, of the dozens of militants belonging to the Sunni Islamist group Lashkar-e-Jhangvi -- who were arrested by Pakistani authorities for killing Hazaras -- only a handful have been convicted.