Gunmen shot and killed at least 22 people in southwest Pakistan on Monday, after forcing them out of vehicles and checking their ethnicity, government officials said, Paralel.Az reports citing foreign media.

The attack happened early Monday in the district of Musakhail in impoverished Balochistan province, where security forces are battling sectarian, ethnic and separatist violence.

"At least 22 people were killed and 5 injured when militants stopped several busses, trucks and vans on a highway connecting Punjab with Balochistan," Najibullah Kakar, a senior official in Musakhail, told AFP.

"Vehicles traveling to and from Punjab were inspected, and individuals from Punjab were identified and shot," he added.

He said 19 Punjabis and 3 Baloch were killed, mostly Punjabi labourers.

Hameed Zehri, another senior official in the district, confirmed the death toll to AFP.

"It seems that the BLA (Baloch Liberation Army) terrorists are behind the incident," he said.

The Baloch Liberation Army is the most active militant separatist group in the region.

Balochistan is Pakistan's largest but poorest province, despite an abundance of untapped natural resources.