Quetta, Pakistan CNN  —  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. The Baloch Liberation Army (BLA), a militant separatist group active in the restive and mineral-rich southwestern Balochistan province, claimed responsibility for the attack. Around 450 passengers were on the Jaffer Express enroute from Balochistan’