N. Korea army vows 'merciless' response to US provocation

North Korea's army on Friday vowed a 'merciless' response to any US provocation, as tensions soar over Pyongyang's nuclear programme and speculation mounts that it is preparing a fresh weapons test.Pyongyang's rogue atomic ambitions have come into sharp focus in recent weeks, with United States President Donald Trump vowing a tough stance against the North and threatening unilateral action if China failed to help curb its neighbour's nuclear programme.As hostilities in the region surge Trump has