A suicide car bomb attack struck a convoy of buses carrying security personnel in southwestern Pakistan on Sunday, killing at least five officers and injuring ten others, authorities said.

The bombing occurred in Naushki, a district in the restive province of Balochistan, according to local police chief Zafar Zamanani. The wounded—some critically injured—were rushed to a nearby hospital for treatment.

Following the explosion, gunmen believed to be separatist militants opened fire on the buses. Security forces returned fire, killing at least four of the attackers, Balochistan Chief Minister Sarfraz Bugti confirmed.

The banned Baloch Liberation Army (BLA) claimed responsibility for the attack. The group has waged a long-running insurgency demanding independence from Pakistan, accusing the federal government of political and economic marginalization—an allegation Islamabad denies.

This latest attack comes just a week after the BLA hijacked a train, taking around 400 passengers hostage. That incident ended with 26 hostages killed before security forces launched an operation that left all 33 attackers dead.

Resource-rich but underdeveloped, Balochistan is Pakistan’s largest yet least populated province. The region is rich in natural gas, oil, and minerals, but has long been plagued by violence from separatist groups and militant outfits.