Pyongyang says broadcasts coming from the South are a ‘grave military provocation’ and demands they be halted immediatelyNorth Korea’s military on Saturday warned of imminent strikes on South Korean border units and issued fresh nuclear weapons threats against the US in response to what it called “grave” provocations from both.The warnings came amid escalating military tensions on the Korean peninsula following a landmine attack South Korea blamed on the North and before a major South Korea-US joint military exercise condemned by Pyongyang.