Pence said he would seek to counter North Korea's attempt to use the Olympics for propaganda and invited the father of Otto Warmbier, an American student who died past year after being imprisoned in North Korea for 17 months, to the Games in Pyeongchang. Then when the Korean team entered the stadium under a unified flag, Pence sat stone-faced while Moon and North Korean officials stood together in applause.
Trump has at times questioned the objective of further talks with the North after years of negotiations by previous US administrations failed to halt the North's weapons programs. The official added that Pence does not believe that the invitation dilutes the toughness of the United States pressure campaign on North Korea.
There is a little public relations trickery at play here, with Intel not making it all that clear that the flight shown during the televised opening ceremony actually took place in December.
In August 2009, the North sent a delegation led by Workers' Party Secretary Kim Ki-nam to pay condolences to former President Kim Dae-jung, who passed away that month and organized the first inter-Korean summit.
North Korea has spent years developing its military, saying it needs to protect itself from U.S. aggression. The United States fought with South Korea and maintains tens of thousands of troops and an "ironclad" agreement to protect its ally.
Speaking on his way home from the Winter Olympics in South Korea, Mr Pence said there was "no daylight" between the two allies on the issue.
"What can not be overlooked is that Moon did not directly demand North Korea to abandon its nuclear development". The conflict, which was sparked by a North Korean vessel crossing the de facto maritime border between the Koreas, left six South Koreans and 13 North Koreans dead.
The South Korean president has been invited to travel to North Korea, following a formal invitation from the country's leader Kim Jong Un, according to a Blue House spokesman.
"It is too early to say if. using the Olympics in a way to reduce tensions, if that is going to have any traction once the Olympics are over, we can't say right now", Mattis said.
Later, Pence echoed the tough stance being taken by Donald Trump against Kim Jong Un's continued nuclear tests.
How significant is Kim Jong-Un's sister's visit to South Korea and the meeting with the South's president in particular, in your view?
The vice president's visit was also marked by bad blood between Pence and some US athletes.
The US has given mixed signals about its willingness to talk.
In a rare honour for visiting foreign guests, Moon met Kim's sister, Kim Yo Jong, four times during the delegation's three-day visit.
Ms Kim, who is though to be about 30 years old, was promoted to the powerful politburo last year.
At a post-match press conference, North Korean player Jong Su Hyon sang the joint team's praises, saying, "One united is stronger than two divided".
As the Week noted, the International Olympics Committee has formally banned Russian Federation from participation in the games but allowed 169 athletes to compete under a neutral flag.