Later on Saturday Ms Kim, Kim Yong-nam and Moon Jae-in attended the first ice hockey match played by a unification team of athletes from both North and South Korea.
Cameras caught Pence not standing as the 143 athletes entered the stadium.
North Korea agreed to participate in Pyeongchang after Games host South Korea and the International Olympic Committee encouraged the reclusive, heavily sanctioned state to participate as a gesture of peace.
North Korea has sent some of the highest level officials ever to the south for these games, the result of diplomacy by Seoul that led to an agreement between the two countries - still formally at war - to participate together in the Winter Games.
The report also highlighted the joint entry by the two teams of the DPRK and South Korea into the stadium.
Kim Yo-jong's arrival was broadcast live on South Korean television.
Pence said the usa would "demand at the outset of any new dialogue or negotiations that the Kim regime put denuclearization on the table and take concrete steps with the world community to dismantle, permanently and irreversibly, their nuclear and ballistic missile programs".
Park also dryly pointed out that the last-minute participation of the North Koreans meant some South Korean athletes who had planned to play were ruled out, a fact some South Koreans continue to resent. It would be the first meeting of leaders of North and South Korea since 2007. With that, he had met with all the delegates and heads of state from the four key powers in the region, minus Russian Federation, since he'd met with U.S. Vice President Mike Pence and Chinese Special Envoy Han Zheng just a day before.
The live show was meant to be a pared down version of the feat, with 300 drones flying at the end of the opening ceremony, but that too was scrapped. Still, as the Opening Ceremony got underway, a number of confused viewers took to social media to inquire about what appeared to be sections of empty seats.
Moon did not respond directly to the invitation from Kim Jong Un, and urged Pyongyang to actively seek an "absolutely necessary" dialogue with Washington, Moon's spokesman said. Mr Pence did not meet with the North Korean delegates, spokeswoman Alyssa Farah said.
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