North Korean regime shake-up gives Kim Jong Un a new second-in-command, South Korean media says Video: S.Korean president: 'Time to take action' on N.Korea (Reuters) S.Korean president: 'Time to take action' on N.Korea Replay Video UP NEXT A shake-up of the North Korean leadership has created a de-facto position of second-in-command under Supreme Leader Kim Jong Un, according to South Korean media. The dictator, who is believed to be in his late 30s, cemented his power at the congress of the Workers' Party of Korea in January, in which he was elected its general secretary. That position was last held by his late father Kim Jong Il.