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.

After more than a day of fighting with separatist militants who hijacked a train carrying hundreds of passengers, Pakistan’s army said it had brought the insurgent attack to an end, but that 21 passengers and four paramilitary personnel had been killed.