Tension between North and South Korea has flared again, with the north warning of what it calls an “indiscriminate pre-emptive nuclear strike of justice”. <br /><br /> The new threat to turn the US and South Korea into what Pyongyang calls a “sea of flames and ash” comes as the two allies begin annual military exercises.<br /><br /> A fourth nuclear test by the north and a long-range rocket launch last month have angered Seoul and Washington and tough new UN sanctions were imposed.<br /><br /> South Korean Defence Ministry Spokesman Moon Sang-Gyun told a media conference:<br />“North Korea should immediately stop its rash and reckless behaviour that leads to self-destruction. <br /><br /> “If North Korea ignores our warning and makes provocations, our military will firmly and mercilessly respond to it.”<br /><br /> The US and South Korea say have informed the north that the exercises are clearly for “training” only and are “non-provocative”.<br /><br /> But the deployment of 17,000 American troops and 300,000 South Korean soldiers has been condemne
