South Korea has paid tribute to wartime Korean forced laborers at Japan’s Sado gold mines in a memorial ceremony.

South Korea expressed regret to Japan on Monday over Tokyo's attitude towards a memorial service held for labourers including Koreans forced to work in Japan's Sado mines during World War Two, Seoul's foreign ministry said.

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.

After boycotting one organised by Tokyo, South Korea held its own memorial event on Monday for compatriots forced to work in a Japanese mine during World War Two, highlighting lingering sensitivities between the countries.

North Korea condemned on Saturday recent joint military drills by the United States, South Korea and Japan, warning that it would take immediate actions if needed to defend the state. Last week, the three countries held a three-day joint exercise,

South Korea has expressed regret to Japan over the way Tokyo has handled the memorial ceremony for the wartime forced labor victims, including Koreans, from an old Japanese mine complex during World War II,

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 strain relations between the two sides.