It remained unclear whether Ms. Kim would be carrying a message from her brother to Mr. Moon, who has said he is willing to meet Kim Jong-un if he is reasonably sure that such a meeting would help end the crisis over the North’s nuclear weapons and missile development.
The North Koreans’ trip has raised hopes within Mr. Moon’s government, which has sought to use the North’s participation in the Olympics to expand dialogue with North Korea and ease tensions over the North’s nuclear weapons program. North Korea is sending 22 athletes to the Olympics, as well as hundreds of cheerleaders, musicians, singers and dancers.
The two Koreas will march together in Friday night’s opening ceremony in the South Korean town of Pyeongchang, and even field their first-ever joint Olympic team, in women’s ice hockey. Mr. Pence also plans to attend the opening ceremony.
But hopes for détente have been tempered by deep skepticism over the North’s sudden overtures. United States officials fear that after a year of increasingly provocative missile and nuclear tests, Kim Jong-un may be on a charm offensive to undermine international sanctions that have begun biting his isolated country.
Before leaving Japan for South Korea, Mr. Pence said the United States would not be duped by any false overture.
“We’ll continue to seize every opportunity to ensure that North Korea does not use the powerful imagery and backdrop of the Olympics to paper over an appalling record of human rights and a pattern of developing weapons and conducting the kind of missile launches that are threatening our nation and threatening neighbors across the region,” Mr. Pence said.
Mr. Pence met with Mr. Moon later on Thursday, and both reaffirmed a principle of “using maximum sanctions and pressure to bring North Korea to the negotiating table for denuclearization,” said Mr. Moon’s spokesman, Yoon Young-chan.
Before meeting Mr. Moon, Mr. Pence said he would seek a South Korean commitment to “continue to isolate North Korea economically and diplomatically so that we can achieve what the world has longed to see, which is a nuclear-free Korean Peninsula.”
Mr. Moon has supported American-led sanctions against the North, but he has repeatedly called for dialogue. He has also been a vocal critic of any use of military force against North Korea, which is being considered as an option in the Trump administration.
In his meeting with Mr. Pence, Mr. Moon again emphasized the need for talks with North Korea, saying that he hoped that the inter-Korean dialogue started by the North’s participation in the Olympics would lead to broader talks on resolving the North Korean nuclear crisis, Mr. Yoon said.
With North Korea’s decision to send a high-level delegation, the Winter Olympics have suddenly become an arena for high-profile diplomacy. Although North Korea said its delegates had no willingness to meet Mr. Pence, the vice president again did not rule out the possibility of a meeting on the sidelines of the Games.
“There may be a possibility for any kind of an encounter with North Koreans, whether it be informal or whether it take the form of a meeting,” he said. “As I said, we’ll have to wait and see exactly how that unfolds.”
In a jarring contrast to the moves toward reconciliation in the South, columns of goose-stepping soldiers and vehicles carrying rockets, including intercontinental ballistic missiles, rolled through the main square in Pyongyang, the North Korean capital, on Thursday as the country celebrated its Army Building Day.
“We must ensure that no invaders can infringe upon our dignity and independence,” Mr. Kim said in a speech delivered from the podium overlooking the parade. “The People’s Army must keep in high alert and redouble its preparations for battle as the United States and its followers are making a fuss around the Korean Peninsula.”
It was the first parade since Mr. Kim declared in his New Year’s Day speech that a “nuclear button” on his desk could launch weapons targeting the mainland United States. The missiles on display on Thursday included the Hwasong-14 and Hwasong-15 ICBMs, which the North test-launched last year.
Other military parades in recent years were broadcast live, but the event on Thursday aired several hours later.
Some analysts in the South said that the North might have decided not to ruffle too many feathers as its athletes and officials were abroad.
Conservative South Koreans have vehemently accused the North of trying to “steal the show” by staging a military parade the day before the Winter Olympics begin.