An operation is underway in southwestern Pakistan to rescue hostages taken by separatist fighters who hijacked a train carrying over 400 passengers.



The militants attacked the train on Tuesday in Balochistan Province as it was traveling from the provincial capital Quetta to Peshawar.



Security sources say 155 passengers have been rescued so far, but Reuters says dozens are still being held hostage.



A released passenger Bashir Yousaf spoke of his experience. He said that all the passengers were crying and shouting, and lying on the floor trying to stay alive. He also said the sound of gunfire was coming from everywhere.



An anti-government armed group called the Baloch Liberation Army, or BLA, has claimed responsibility for the attack.



The Pakistani government is working with China in the mineral-rich province to harvest natural resources and build seaports. The BLA insists that such government projects are unjust exploitation, and has carried out frequent attacks in recent years.