SEOUL, South Korea — North Korea said Thursday it had successfully tested a multiwarhead missile in the first known launch of a developmental weapon coveted by leader Kim Jong Un to overwhelm US and South Korean missile defenses. South Korea quickly dismissed the claim as deception to cover up a failed launch.

North Korea's state media said the launch Wednesday tested the separation and guidance control of individual mobile warheads to ensure the capability of the Multiple Independent Reentry Vehicles. It said the separated warheads 'were guided correctly to the three coordinate targets' and a decoy that separated from the missile was verified by radar.