A North Korean propaganda unit said the U.S. ambassador to South Korea could face a "bigger mishap" than the knife attack to his face last month if he does not stop insulting North Korea with "laughable" accusations.

U.S. envoy Mark Lippert said in a speech Wednesday that if North Korea improves its human rights record and takes steps to end its nuclear program, it will be rewarded with prosperity and better ties with the outside world, including with the United States.

The North's Committee for the Peaceful Reunification of Korea said Lippert's remarks are proof that Washington is intent on hostility.