Why North Korea is turning up the heat again? - Key Rsolve Exercise
North Korea has vowed to disregard the 1953 truce that ended the Korean War, in response to South Korea's joint military drills with the US. North Korea has threatened to cancel the truce that ended the Korean War if South Korea continues its joint military exercises, 'Key Resolve', with the United States. North Korea's military accused the two allies of "hostile policies" and said it would respond with "more and stronger countermeasures. Pyeongyang says it will also recall its delegates from Panmunjom, the border village where the 1953 armistice was signed and where the North and South's negotiators still meet for talks.
South Korea's military must be fully prepared to strike back at the North if its neighbor uses military force. If North Korea undertakes provocation and threatens peace, South must make it clear that they have all preparations in place for a strong and decisive punishment not only against the source of the aggression and its support forces but also the commanding element.
(http://www.globalpost.com/dispatch/news/regions/asia-pacific/130305/north-korea-korean-war-truce-south-korea)