NIIGATA (Kyodo) -- An event to commemorate Japanese and Korean laborers who worked at the gold and silver mine complex on Japan's Sado Island during World War II was held Sunday, following an agreement between Japan and South Korea to hold the event before the site's addition to UNESCO's World Heritage list earlier this year.

However, South Korean officials and families of the Korean laborers scheduled to participate in the event did not attend, as the country's Foreign Ministry stated Saturday that it was difficult for the two nations to reach a consensus on the event.

Seoul's announcement followed a statement by Tokyo that Parliamentary Vice Foreign Minister Akiko Ikuina would attend the event. South Korean media reported that Ikuina has visited the war-linked Yasukuni Shrine in Tokyo, a frequent source of diplomatic friction with South Korea and other Asian nations.

At the event, Ikuina said, "The laborers who came from the Korean peninsula took on difficult work in a dangerous and harsh environment" of the mine, adding she pays respects to the efforts made by all the mine laborers and mourns for those who died.

Ikuina told reporters that she had not visited the Yasukuni shrine since she was elected to the House of Councillors in 2022.

The mine complex was added to UNESCO's World Heritage list in July following a last-minute agreement from South Korea, which had initially opposed the listing, citing links to the wartime forced labor of Koreans.

One of the conditions agreed upon by the two countries at the time was that Japan would hold an annual memorial event to commemorate all laborers.

Japan maintains that wartime requisition does not constitute forced labor under international law. In her speech at the event, Ikuina did not mention the coercive nature of the Korean laborers' work at the mine.