A Pakistani official says a bomb planted on a railway track killed three passengers in a passing train and wounded seven others in the southwest.

Railways spokesman Maqbool Ahmed says the bombing in Baluchistan province early Sunday targeted a train bound for Rawalpindi, where the military is headquartered.

He says the powerful explosion damaged the first car and part of the track. He says the track has been repaired and traffic restored.

No one claimed responsibility, but separatist groups in the region have claimed similar attacks in the past.

For over a decade, Baluchistan has been the scene of a low-intensity insurgency by ethnic Baluch separatists who want autonomy or outright independence.