QUETTA, Pakistan — A roadside bomb exploded in Pakistan’s southwestern Baluchistan province, killing three people, police said.

Police officer Mohammad Rahim said the bomb was planted on a dirt road in the Balgatar area of Kech district and was detonated remotely. Three men, two of whom were brothers, were killed while on their way to a family gathering, and a privately owned car was destroyed, he said.

No group immediately claimed responsibility for the blast but suspicion falls on Baluch nationalists turned separatist groups who have been involved in low-level insurgency for over two decades in the gas- and mineral-rich province. The groups have been calling for independence from the central government in Islamabad.

Kech district and surrounding areas have suffered from violence for years. Insurgent groups have claimed responsibility for attacks on security forces and civilian targets in recent months.

Islamic militants and a banned Sunni extremist group also operate in the province.

Also Sunday, police in the Rajanpur district of the southwestern Punjab province arrested four militants in a raid.

Dost Muhammad, police chief in Rajanpur, said officers seized explosive material and weapons from the militants’ hideout. He did not say which group the militants belong to but said anti-state elements from Baluchistan often sneak into the border area of his district.