North Korea has apparently started preparations to resume reunions of families separated by the 1950-1953 Korean War as instructed by leader Kim Jong Un, a source close to the matter said Friday, in another sign of a thaw in inter-Korean relations.

The topic may be discussed during envisioned talks between South Korean President Moon Jae In and Pyongyang's high-ranking delegation to Sunday's closing ceremony of the Pyeongchang Winter Olympics, the source said.

The family reunion program has not taken place since October 2015. South Korea has called for the resumption of the program, but North Korea has rejected the request.

Pyongyang said Thursday that the delegation led by Kim Yong Chol, the head of the North Korean ruling party's United Front Department, will make a three-day trip to South Korea from Sunday. Seoul said the delegation plans to meet with Moon during its visit.

The reunions of separated families have been held on and off since a landmark summit between the two Koreas in 2000.

The issue is regarded as an urgent humanitarian matter as many members of divided families are of advanced age and strongly wish to see their relatives on the opposition side of the border before they die.

Park Kyung Seo, chairman of the South Korea's Red Cross, said earlier this month that he has had contacts with North Korea's Red Cross for the past five months and Pyongyang has shown signs of accepting Seoul's offer to resume the reunions.

North Korea has been reluctant to hold the reunions, urging Seoul to first return women who are believed to have escaped to South Korea from a North Korean government-run restaurant in China in 2016.

More than 10 million Koreans have close relatives living on the other side of the border, separated during or in the immediate aftermath of the Korean War.

Nearly 131,000 people have registered with the South Korean government to take part in the program until the end of January, but about 73,000 have already died without being able to meet their family in the North.