Baloch fighters are creating terror in Pakistan, why are people of Punjabi origin on their target, when did the big attacks happen?

The internal conflict in the neighbouring country Pakistan is not stopping. Recently, local militants in Balochistan carried out a major attack and targeted police station, railway line and highway, in which more than 70 people died. The militants also killed Punjabi travellers after asking for their identity. The Baloch Army has carried out target killings