The United States and South Korea conduct a joint military exercises . A North Korean flag is used in the live - fire exercise . Pyongyang says that constitutes a grave provocation . Seoul , South Korea ( CNN ) -- North Korea has reacted angrily to the use of its flag during live-fire drills by South Korea and the United States , calling it `` a grave provocative act . '' South Korea says the flag was to mark territory and was not used as a target .
The United States and South Korea conduct a joint military exercises . A North Korean flag is used in the live - fire exercise . Pyongyang says that constitutes a grave provocation . South Korea says the flag was to mark territory and was not used as a target .