Pakistan’s military have been engaged in a deadly standoff for more than 24 hours with armed militants who hijacked a train and took hostages, in a dramatic escalation of an insurgency that has plagued the region for decades.

Pakistan forces launched a "full-scale" operation on Wednesday to rescue train passengers taken hostage by militants in the mountainous southwest, with security sources saying 155 had been freed in the past 24 hours.

Who are the militants behind Pakistan train hijacking? - Baloch separatist outfit is designated as a terrorist group by Pakistan and the US