Kim Hyok Chol was executed in March at Mirim Airport in Pyongyang, along with four foreign ministry officials after they were charged with spying for the United States, the Chosun Ilbo reported, citing an unidentified source with knowledge of the situation.

"He was accused of spying for the United States for poorly reporting on the negotiations without properly grasping U.S. intentions," the source was quoted as saying.

The February summit in Vietnam's capital Hanoi, the second between Kim and Trump, failed to reach a deal because of conflicts over U.S. calls for complete denuclearisation of the Korean peninsula and North Korean demands for sanctions relief.

Reuters was unable to independently confirm the report. Previously, some North Korean officials who were reported to have been executed or purged reappeared later with new titles.