Kim Yo Jong also was due to attend the unified Korean hockey team's first Olympics match, a spokesperson for South Korea's presidential office told CNN.
The pair were photographed by a wire service giving each other a fist bump before getting the boot.
North Korean leader Kim Jong Un presided over an extravagant military parade in Pyongyang's Kim Il Sung Square on Thursday, grabbing the spotlight on the eve of the Pyeongchang Winter Olympics in South Korea to thumb his nose at Washington while making a point of showing off his new-found restraint toward Seoul. South Korean participants included senior officials Jeong Eui-yong, Jo Myong-gyoon and Im Jong-suk, the chief presidential secretary. The group is fringe, but their demonstrations have generated irate reactions in 's state-run media and could potentially spin out into a major incident if they ever manage to get closer to the North Koreans themselves - or especially and her entourage. Kim Yo-jong, in fact, was seated nearly directly behind the US vice president.
He also ratcheted up his rhetoric on the North's human rights abuses in a speech to USA service members at Yokota Air Base in Japan.
U.S. vice-president Mike Pence, who was seated in the same box, did not interact with the North Koreans at any point, United States officials said.
Xiaomi Mi 7 Smartphone - Everything You Need to Know
The leak also mentions the presence of a 12-megapixel optical zoom dual camera and global 4G LTE bands support for the Mi Mix 2S . Apart from this, some major changes are made to the phone's hardware that already make it much better than its predecessor Mi 6.
The U.N. says Secretary-General Antonio Guterres had a brief exchange with North Korea's nominal head of state and "reiterated his expectation and hope that all parties will use dialogue to achieve the denuclearization of the Korean Peninsula". Jo Yong Sam, department director general of North Korea's foreign ministry, said Thursday the country had never "begged the U.S. for dialogue" and wasn't about to start now. "But we'll see what happens".
Kim Yo Jong, who is believed to be about 30, has been rapidly rising within the North's power structure and is believed to be in charge of shaping her brother's public persona.
Moon is eager to use Kim's presence at the games to restore regular communication with North Korea and eventually pull it into nuclear talks.
Aides acknowledged that the vice president's cynical message is an unusual one for Pence, but said the circumstances warrant the tone. They said Pence could have opted to sit with the USA delegation and avoided the box that included the North Koreans.
Japanese Prime Minister Shinzo Abe has warned South Korean President Moon Jae-in not to fall for North Korea's "smile diplomacy" during the Olympics, saying the North remains committed to developing nuclear weapons and missiles even while pursuing talks with the South.
Mr Pence seeks to counter what he called North Korean "propaganda" around the Winter Olympics, and is eager to put a reality check on the thaw in relations between the Koreas in advance of the Games.