Kim Jong Un's sister keeps lunch date with South Korea's president

South Korean President Moon Jae-in, center, shakes hands with Kim Yo Jong, left, sister of North Korean leader Kim Jong Un. (Kim Ju-sung/Yonhap via AP)

A possible thaw in diplomatic relations between North and South Korea continued over lunch Saturday at the Blue House in Seoul, residence of South Korean President Moon Jae-in.

Moon's guests were Kim Yo Jong, younger sister of North Korean leader Kim Jong Un, and other senior delegates from Pyongyang, whose visit to South Korea is coinciding with the 2018 Winter Olympics in Pyeongchang, South Korea.

On Friday, Kim Yo Jong, 28, became the first member of the Kim family to cross into the South since the 1950-53 Korean War. The lunch marked the first time a North Korean delegation was hosted at the Blue House since November 2007.

South Korean President Moon Jae-in, third from right, speaks to Kim Yo Jong, second from left, sister of North Korean leader Kim Jong Un, and North Korean delegation during a meeting at the presidential house in Seoul, South Korea, Feb. 10, 2018. (Kim Ju-sung/Yonhap via Associated Press)

South Korean television showed Kim Yo Jong and other officials, including the North’s nominal head of state Kim Yong Nam, smiling and shaking hands with Moon in the presidential palace’s reception room.

“I appreciate you stayed late out in the cold. Are you all well?” Moon asked the delegation.

Moon and Kim Yo Jong first came face-to-face at Friday’s Olympic opening ceremony, where they shook hands and praised athletes from the two Koreas as they marched holding a blue-and-white flag symbolizing a unified Korean Peninsula.

Kim Yo Jong, considered to have her brother's absolute trust, sits to meet South Korean President Moon Jae-in at the presidential house in Seoul, South Korea, Saturday, Feb. 10, 2018. (Kim Ju-sung/Yonhap via AP)

At Saturday’s meeting, Kim Yo Jong held what appeared to be a blue folder, which local media speculated may have contained a personal message from her older brother.

“If there is a message to be conveyed to South Korea or the U.S., she is amply well positioned to convey it,” Christopher Green, a senior adviser on Korean affairs at the International Crisis Group think tank, told Reuters.

Kim, one of the few people considered to have earned her brother’s absolute trust, serves as first vice director of the Central Committee of the country’s ruling Workers' Party. She is considered more important than Kim Yong Nam in North Korea even though she ranks diplomatically lower, Reuters reported.

Kim Yo Jong, center, is thought to be more important in North Korea than the country's nominal head of state Kim Yong Nam, second from left. (Kim Ju-sung/Yonhap via AP)

Moon, meanwhile, has hoped use the Olympic Games to restore regular communication with the North and create an opportunity to resolve the tense international standoff over its nuclear program.

Moon had offered during his inauguration speech last year to attend a summit with Kim Jong Un if that would help solve the nuclear dilemma. However, it was unclear if Saturday’s meeting could be used as a foundation for larger meetings between the two countries.

Japanese Prime Minister Shinzo Abe and U.S. Vice President Mike Pence have warned Moon against falling for North Korea’s “smile diplomacy” during the Olympics.

The luncheon was the first time a member of the North’s ruling family member ever visited the Blue House, where in January 1968 North Korean President Kim Il Sung sent a commando squad in a thwarted assassination attempt on South Korea’s then-President Park Chung-hee.

The Associated Press contributed to this report.