QUETTA, Pakistan — A suicide car bomber struck a school bus in southwestern Pakistan on Wednesday, killing five people — including three girls — and wounding 53 others, mostly children, officials said, the latest attack in tense Balochistan province.

The province has been the scene of a long-running insurgency, with an array of separatist groups staging attacks, including the outlawed Balochistan Liberation Army, or BLA, designated a terror group by the United States in 2019.

A local deputy commissioner, Yasir Iqbal, said the attack took place on the outskirts of the city of Khuzdar as the bus was taking children to their military-run school.

No group immediately claimed responsibility for the attack but suspicion is likely to fall on ethnic Baloch separatists, who frequently target security forces and civilians.

Pakistan’s Interior Minister Mohsin Naqvi called the perpetrators “beasts” who deserve no leniency, saying the enemy had committed an act of “sheer barbarism by targeting innocent children.”

— The Associated Press