The delegation also includes Choe Hwi, chairman of the National Sports Guidance Committee, and Ri Son-gwon, chairman of the Committee for the Peaceful Reunification of the Country - an agency that deals with inter-Korean affairs. He also saidWashington may see Kim Yo Jong as an avenue to deliver messages to Kim Jong Un.
"And that is that North Korea must once and for all abandon its nuclear weapons program and ballistic missile ambitions".
Kim Jong Un's sister, Kim Yo Jong, is a close adviser to Kim Jong Un.
"It is highly significant that a member of the Kim family is coming to the South for the first time in history", said professor Yang Moo-Jin of the University of North Korean Studies in Seoul.
Kim Jong Un might also have seen that U.S. President Donald Trump was sending his daughter, Ivanka, to the Olympics closing ceremony and made a decision to match the move by sending his sister, said Hong Min, an analyst at Seoul's Korea Institute for National Unification.
Under her brother's leadership, Kim Yo Jong has taken on more responsibility, dealing with policy, receiving intelligence briefings and acting "almost like a White House chief of staff would", said Madden.
The squad, which features women chosen for their youth, good looks and enthusiasm, has been allowed to root for the North's much smaller contingent of athletes - only about 22 are competing - as part of a last-minute arrangement between Pyongyang and Seoul.
US Vice President Mike Pence will also attend Friday's opening ceremony in Pyeongchang and has not ruled out meeting North Koreans. Although the fund is legal and monies will not flow into North Korea, questions have been raised over whether South Korea should cover the cost of Pyongyang's delegation.
Kim's presence, alongside Kim Yong Nam (no relation), the 90-year-old ceremonial head of state in North Korea, will raise hopes for a potential breakthrough in relations with the US. As the vice director of the Workers' Party Propaganda and Agitation Department, she has been targeted by U.S. sanctions.
"As President Trump has said, past experience has taught us that complacency and concessions only invite aggression and provocation" from North Korea, Pence told reporters here. The ship's first visit to South Korea in 16 years came about after Seoul temporarily lifted some bilateral sanctions.
While publicly supportive of the North-South talks over the Olympics issue and the subsequent cooperation, the United States is wary of allowing North Korea's government to gain economic concessions from the south through its so-called "charm offensive". In a statement, South Korea's Unification Ministry called the composition of the delegation "meaningful".
Seoul's Foreign Ministry maintains that it will not stoke any controversy regarding sanctions, saying it is closely coordinating with the U.S. and the global community on the matter.
President Donald Trump has criticised the policy of previous United States administrations towards North Korea and has already convinced the global community to significantly tighten sanctions against Pyongyang. Some in the worldwide community worry these moves could create loopholes in the sanctions regime against North Korea.
"Under the best of circumstances, it's going to be incredibly hard to get North Korea to get rid of nuclear weapons, short of the use of military force".
In the murky world of North Korean politics, Kim Yo Jong also plays an important role as an informant for her brother, according to North Korean analyst Ken Gause.
Several accidents halt traffic on Gov. Mario M. Cuomo Bridge
Commuters were warned to expect extensive traffic delays on I-87, the Henry Hudson Parkway, and the George Washington Bridge. All lanes on both sides of the bridge were closed as ambulances and tow trucks responded to the scene, snarling traffic.