The South Korean president said he will help Washington and Pyongyang reach a deal on denuclearisation, after talks failed in Hanoi.
Moon Jae-in was speaking in Seoul, on the country's 100th independence movement day.
South Koreans had hoped there would be additional celebrations after the Vietnam summit, but the results of the talks, or lack thereof, left little to cheer.
Al Jazeera's Rob McBride reports.
