North Korea has threatened to "retaliate against the US with tremendous muscle" unless the US cancels its planned multinational military exercises.
The exercises, which occur every year in South Korea, are scheduled to start tomorrow (Monday). A statement by the Korea-US Combined Forces Command says that the purpose is "to enhance... readiness, protect the region and maintain stability on the Korean peninsula."
The State Department says that North Korea's threats also occur every year and that it does not take them seriously.