PYEONGCHANG-GUN, SOUTH KOREA - FEBRUARY 09: Performers entertain during the Opening Ceremony of the PyeongChang 2018 Winter Olympic Games at PyeongChang Olympic Stadium on February 9, 2018 in Pyeongchang-gun, South Korea.
Earlier Kim Yo Jong and other North Korean delegates attended the opening ceremony of the Pyeongchang Winter Olympics, which has brought a temporary lull in tensions over the North's nuclear programme.
In the front row of the grandstand, United States' Vice-President Mike Pence stood to wave and applaud the US team as they made their circuit of the stadium.
The handwritten invitation to President Moon was delivered by Mr Kim's influential sister, Kim Yo-jong, at a landmark meeting in the presidential palace in Seoul, as the Games opened on Saturday.
"It was a great moment", said International Olympic Committee spokesman Mark Adams during the first daily briefing of the Games.
Prior to his arrival in South Korea, Pence told reporters in Japan part of the reason for his visit was to counter North Korean propaganda.
Cho's mother was captured by North Korean troops during Korean War.
UN Secretary-General Antonio Guterres urged North Korea's ceremonial head of state Kim Yong Nam to engage in dialogue on ending the nuclear crisis during a brief exchange in South Korea , a UN spokesman said Friday.
"Make no mistake about it, the United States of America has viable military options to deal with a nuclear threat from North Korea but, that being said, we hope for a better path", he said.
According to South Korea's Yonghap News Agency, internet-based telecasts were disrupted, and some people who bought tickets online for the opening ceremony said they couldn't print their tickets.
South Korean figure skater Yuna Kim performs before lighting the Olympic cauldron.
North Korea is paranoid that its Olympic stars could defect from the country.
If a summit does go ahead, it will be the first between the two Koreas since 2007.
As Switzerland demolished a unified Korean women's hockey team at the Winter Olympics, a far more diverting competition took place on the sidelines. Moon, who was seated in front of the North Korean delegation, was photographed shaking hands with a smiling Kim.