North Korea fires short-range ballistic missiles, says Seoul / North Korea holds missile-launch drills supervised by leader Kim Jong-un / North Korea fires missiles into Sea of Japan, South Korea says / North Korea launches short-range ballistic missiles into sea, South Korea says / South Korea says North Korea has fired at least one ballistic missile toward sea / South Korea says North Korea has fired at least one ballistic missile toward the sea / North Korea confirms soldiers sent to fight with Russia against Ukraine