South Korea paid tribute to wartime Korean forced laborers at Japan’s Sado Island Gold Mines in a memorial ceremony on Monday, a day after boycotting a similar event organized by Japan, as tensions over historical atrocities continue to impact relations between the two sides.

Japan has held a memorial ceremony near the Sado Island Gold Mines despite a last-minute boycott of the event by South Korea that highlighted tensions between the neighbors over the brutal wartime use

The event came after the Sado Island Gold Mines were designated a UNESCO World Heritage site earlier this year.

South Korea’s government says it has decided not to attend a memorial service near Japan’s Sado Island Gold Mines due to unspecified disagreements with Japan over the event, which stirred longstanding tensions over the abuse of Korean forced laborers at the site before the end of World War II.

South Korea held a memorial event in Japan to honor laborers forced to work during WWII, boycotting a Japanese-organized event due to sensitivities over historical disputes. Improved ties between Seoul and Tokyo face challenges as both nations navigate diplomatic relations tied to colonial history.

An event to commemorate Japanese and Korean laborers who worked at the gold and silver mine complex on Japan's Sado Island during W

Efforts by South Korea and Japan to hold a joint memorial service near Japa’s Sado Island Gold Mines, where Koreans were forced to work during Japan’s colonial rule, fell apart on Nov. 24 due to disagreements between both governments.