By Asif Shahzad ISLAMABAD (Reuters) -Attackers wearing suicide bombs were sitting next to passengers taken hostage after militants took over a train in southwest Pakistan, sources said on Wednesday, complicating rescue efforts a day after the country's first such hijacking.

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.

Pakistani security forces exchanged gunfire on Wednesday with hundreds of separatist militants as they sought to free about 300 hostages aboard a train in the country’s rugged southwest, officials said.