North Korean leader Kim Jong Un's younger sister, Kim Yo Jong, attended the opening ceremony of the Pyeongchang Winter Olympics in South Korea on Friday, a historic moment that brings hope for easing security tensions sparked by Pyongyang's nuclear weapons ambitions.

During the ceremony, Kim Yo Jong, who is a member of North Korea's high-ranking delegation to the Olympics and considered one of the closest aides to her brother, shook hands with South Korean President Moon Jae-in on their first encounter, TV footage showed.

When North and South Korean athletes jointly marched into the stadium under a unified Korean flag, Kim, wearing a black coat, waved with Moon before shaking hands again as they stood together with the other delegates from Pyongyang.