ISLAMABAD — Gunmen have killed at least 20 people at a coal mine in Balochistan province in southwestern Pakistan, according to local police.

The attackers stormed the workers' accommodation at the Junaid Coal Company mines in the province's Duki district in the early hours of Friday morning, rounded the men up and opened fire.

A hospital in Duki has received 20 bodies and is treating six injured people, reported Reuters.

The workers were attacked with heavy weapons, including rockets and grenades, police were quoted as saying.

The attackers also set fire to machinery at the mine.

Police have confirmed that four of the victims were Afghans, while the rest of the men were from Pashto-speaking areas of Balochistan.

Businesses closed on Friday ahead of an expected protest in Duki's main square.

So far no group has claimed immediate responsibility for the killings, but in the past the separatist Baloch Liberation Army (BLA) has carried out several deadly attacks in the province.

On Monday, a BLA militant killed two Chinese nationals and injured at least 10 people in a suicide attack near Karachi airport.

The group, which pushes for an independent Balochistan, also committed multiple attacks in August that killed more than 50 people. Pakistani authorities responded by killing 21 insurgents in the province.

The latest attack on the miners drew condemnation from Balochistan's chief minister Sarfraz Bugti, who said the attackers had an agenda to destabilise Pakistan.

“The terrorists have once again targeted poor labourers... the killing of these innocent laborers will be avenged,” he said in a statement.

Balochistan is home to several separatist groups, who accuse the central government of exploiting the resource-rich province.

The militants often target security forces, as well as people who have come to work at the province's many mining and infrastructure projects.

The recent violence comes ahead of the Shanghai Cooperation Organisation, a major security summit being hosted in the Pakistani capital Islamabad next week.

As well as enhancing security measures, Pakistani authorities will reportedly be curbing movements of Chinese citizens during the summit, due to the security risk from militant groups targeting them. — BBC