South Korea and the United States will begin their annual joint military drills on Monday, the South's military said Sunday, amid North Korea's warnings of a diplomatic and security crisis.

South Korea and the United States regularly stage military exercises, mainly in the spring and summer, but North Korea has for decades reacted angrily, calling them a rehearsal for war.

The exercises will continue for nine days, mostly consisting of defensive, computer-simulated command post training with minimum personnel but no live field training, the Joint Chiefs of Staff said.