The remains of one of Japan's Sado gold mines are seen on Sado Island, northern Japan, Aug. 19, 2021. AP-Yonhap

Korea said Saturday it will not attend a memorial ceremony in Japan honoring forced labor victims, including Koreans, from an old Japanese mine complex, amid controversy over Tokyo's decision to send a senior official with hard-line views on history to the event.

The decision, made just a day before the planned ceremony, came after Tokyo said Thursday that Akiko Ikuina, a parliamentary vice minister at Japan's foreign ministry, will attend the ceremony as the government representative.

The announcement further stoked doubt about Japan's sincerity in fulfilling its pledge to hold the event to honor the victims, because Ikuina has visited the Yasukuni Shrine, where war criminals are enshrined.

"We have decided not to attend the Sado mine memorial ceremony, scheduled for Nov. 24, taking into account various circumstances surrounding the event," the government said in a message to the media.

"There was insufficient time to reconcile differing positions between the diplomatic authorities of both countries, making it unlikely to reach a mutually acceptable agreement before the ceremony," it said.

The shrine, regarded as a symbol of Japan's militaristic past, has been a source of tension, with Korea strongly opposing visits or offerings made by Japanese government officials.

Critics said her attendance at the ceremony would upset the eleven family members of the Korean victims who were planning to attend the event.

Japan has promised to host a memorial event as a condition for Seoul's consent to the location's designation as a UNESCO World Heritage site.

Many Koreans were taken to toil at the Sado gold and silver mines during World War II, when Korea was under Japan's 1910-45 colonial rule.

Seoul has stressed to Tokyo the importance of holding the ceremony to honor the victims in a sincere manner, requesting the attendance of a high-level official, possibly at a vice minister level.

However, the lack of details about the ceremony's arrangements, even in the days leading up to the event, has sparked speculation in Seoul that negotiations with Japan may not have gone smoothly.

Recent remarks by Hideyo Hanazumi, the governor of the Niigata Prefecture organizing the ceremony, have further fueled concerns. According to Japanese media, Hanazumi said earlier the memorial is intended to report the site's UNESCO listing to the public.

The memorial ceremony is set to take place on western Sado Island, off Japan's west coast, Sunday, with officials from the organizing committee, the Sado city and central governments, and civic groups in Japan expected to attend. (Yonhap)