Ahead of annual , routine military exercises between South Korea and the United States , North Korea issued its usual caustic objections Saturday . It threatened `` miserable destruction , '' if `` your side ignites a war of aggression by staging the reckless joint military exercises ... at this dangerous time . '' Though customary , the stark posturing by North Korea stands in the shadow of an underground nuclear test two weeks ago that was preceded by the launch of a long-range missile capable of transporting a warhead . The detonation of the nuclear charge was the third in Pyongyang 's history and the first under supreme leader Kim Jong Un 's rule . South Korea 's military reacted with fierce military drills , including a public display of newly deployed cruise missiles with pinpoint accuracy . It has been on heightened readiness ever since . The test also triggered a global wave of condemnation , including from Beijing , and plans for new sanctions against Pyongyang . North Korea issued the objections to exercises Key Resolve and Foal Eagle scheduled for March and April to U.S. commander James D. Sherman , state run news agency KCNA reported . The message was delivered over the phone in English , South Korean news agency Yonhap reported . It also condemned the threat of new sanctions over North Korea 's recent actions . A United Nations military commission informed Pyongyang of the upcoming routine exercises , according to a joint statement from U.S. and South Korean military officials . The commission also told North Korea that they are `` not related with the current situations on the Korean Peninsula . '' Around 10,000 U.S. forces will participate in Foal Eagle from March 1 to April 30 . Key Resolve will involve 10,000 South Korean troops and 3,500 U.S. troops in exercises March 11 to 21 . Key Resolve will include U.N. troops and neutral supervisors .
The message was delivered over the phone in English , reports say . Such threat happen routinely before U.S.-South Korean exercises . The exercises come in the wake of a recent nuclear test in North Korea . South Korea 's military is already in a state of heightened alert .