SADO, Japan (AP) — South Korea commemorated wartime Korean forced laborers at Japan's Sado gold mines in a ceremony Monday, a day after boycotting a similar event organized by Japan, as tensions over historical atrocities continue to strain relations between the two sides.

Monday’s ceremony at a former dormitory near the mines on Sado Island, which date back to the 16th century and were listed this summer as a UNESCO World Heritage site, was organized by South Korea’s Foreign Ministry and attended by nine family members of Korean wartime laborers, the country’s ambassador to Japan and other officials.

Japan on Sunday held a memorial service for all workers at the Sado mines, including Koreans. It thanked them for their contributions at the mines but did not acknowledge their forced labor or issue an apology.

At the Korean-sponsored memorial on Monday, participants in dark suits observed a moment of silence and offered white chrysanthemums in honor of the South Korean laborers, along with offerings such as dried fish, sliced apple and pears.

In a short speech, South Korea's Ambassador to Japan Park Choel-hee offered his condolences to the forced laborers and their families, expressing hopes that the memorial would bring comfort to families. He said South Korea and Japan should both make efforts to ensure that the painful wartime history is remembered.

“We will never forget the tears and sacrifices of the Korean workers behind the history of the Sado mines,” Park said.

“I sincerely hope that today will be a day of remembrance for all the Korean workers who suffered indescribable pain under harsh conditions, and that this memorial service will bring comfort to the souls of the deceased Korean workers and their bereaved families,” Park added.

Japan's Chief Cabinet Secretary Yoshimasa Hayashi told reporters Monday that Japan held the ceremony in line with its pledge at the UNESCO World Heritage committee meeting after thoroughly communicating with South Korea. “It is disappointing that South Korea did not participate," Hayashi said.

At the mines, about 1,500 Koreans were forced to labor under abusive and brutal conditions during World War II, historians say.

Sunday's ceremony, which was supposed to further mend wounds, renewed tensions between the two sides. South Korea announced Saturday its decision to not attend the Japanese-organized ceremony, citing unspecified disagreements with Tokyo over the event.

South Korea's Foreign Ministry said Monday that it had decided not to attend the Japan-organized memorial largely because the contents of the government speech at the event were expected to fall short of the agreement between the two sides over the Sado mines' World Heritage site listing.

Holding a separate memorial ceremony was an expression of “our government's firm resolve not to make a compromise with Japan on history issues," it said.

There was speculation that the South Korean boycott was related to the attendance by Japanese lawmaker and former entertainer Akiko Ikuina at Sunday’s ceremony.

Ikuina is controversial in part because there were reports — later withdrawn as erroneous — that after she was elected in 2022 she had visited Tokyo's controversial Yasukuni Shrine. Japan's neighbors view Yasukuni, which commemorates 2.5 million war dead, including war criminals, as a symbol of Japan's past militarism.

Hayashi said “there was no problem” with the government's decision to send Ikuina, who is tasked with culture and public affairs and that Ikuina denied visiting Yasukuni since her term formally began.

Kyodo News on Monday published an apology saying it had erroneously reported Ikuina was among some 20 lawmakers who visited Yasukuni on Aug. 15, 2022.

The Sado mines were registered as a UNESCO cultural heritage site in July after Japan agreed to include an exhibit on the conditions of Korean forced laborers and to hold a memorial service annually, after repeated protests from the South Korean government.

Signs, including one at the site where South Koreans held their ceremony, have been erected indicating former sites of Korean laborers’ dormitories. A city-operated museum in the area also added a section about Korean laborers, but a private museum attached to the main UNESCO site doesn’t mention them at all.

The site of South Korea's memorial was the former Fourth Souai Dormitory, one of four dorms for Korean laborers without families. A newly erected sign there reads, “Workers from the Korean Peninsula lived here during the wartime.”

On Saturday, the families visited a former housing site where Korean laborers lived. They also briefly saw the city-run museum and an exhibit on the Korean laborers as they listened to explanations through a translator.

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Associated Press writers Hyung-jin Kim and Kim Tong-hyung in Seoul, South Korea contributed.

The venue of a memorial service for relatives of Korean victims and South Korean officials is seen in Sado, Niigata prefecture, Japan, Monday, Nov. 25, 2024, after boycotting a memorial organized by Japanese officials. The black banner reads "A memorial service for Korean forced laborer victims at Sado Mine." (AP Photo/Eugene Hoshiko)

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South Korean Ambassador to Japan Park Cheol-hee, center, delivers a speech as relatives of Korean victims and South Korean officials hold a memorial service in Sado, Niigata prefecture, Japan, Monday, Nov. 25, 2024, after boycotting a memorial organized by Japanese officials. (AP Photo/Eugene Hoshiko)

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Relatives of Korean victims and South Korean officials offer flowers during a memorial service in Sado, Niigata prefecture, Japan, Monday, Nov. 25, 2024, after boycotting a memorial organized by Japanese officials. The black banner reads " A memorial service for Korean forced laborer victims at Sado Mine." (AP Photo/Eugene Hoshiko)

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A staff prepare offerings prior to a memorial service held by relatives of Korean victims and South Korean officials in Sado, Niigata prefecture, Japan, Monday, Nov. 25, 2024, after boycotting a memorial organized by Japanese officials. (AP Photo/Eugene Hoshiko)

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South Korean Ambassador to Japan Park Cheol-hee, center, arrives to join the relatives of Korean victims and South Korean officials to hold a memorial service in Sado, Niigata prefecture, Japan, Monday, Nov. 25, 2024. (AP Photo/Eugene Hoshiko)

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South Korean Ambassador to Japan Park Cheol-hee, center, delivers a speech as relatives of Korean victims and South Korean officials hold a memorial service in Sado, Niigata prefecture, Japan, Monday, Nov. 25, 2024. (AP Photo/Eugene Hoshiko)

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South Korean Ambassador to Japan Park Cheol-hee, right, delivers a speech to the relatives of Korean victims and South Korean officials during a memorial service at the site of former Fourth Souai Dormitory for the mine workers from the Korean Peninsula, in Sado, Niigata prefecture, Japan, Monday, Nov. 25, 2024. (AP Photo/Eugene Hoshiko)

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South Korean Ambassador to Japan Park Cheol-hee, left, walks with the relatives of Korean victims and South Korean officials to hold a memorial service at the site of former Fourth Souai Dormitory for the mine workers from the Korean Peninsula, in Sado, Niigata prefecture, Japan, Monday, Nov. 25, 2024, after boycotting a memorial organized by Japanese officials. (AP Photo/Eugene Hoshiko)

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South Korean Ambassador to Japan Park Cheol-hee, front left, looks at a memorial service at the site of former Fourth Souai Dormitory for the mine workers from the Korean Peninsula, in Sado, Niigata prefecture, Japan, Monday, Nov. 25, 2024. (AP Photo/Eugene Hoshiko)

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South Korean Ambassador to Japan Park Cheol-hee, right, bows to an altar as the relatives of Korean victims and South Korean officials during a memorial service at the site of former Fourth Souai Dormitory for the mine workers from the Korean Peninsula, in Sado, Niigata prefecture, Japan, Monday, Nov. 25, 2024. (AP Photo/Eugene Hoshiko)

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South Korean Ambassador to Japan Park Cheol-hee, center, speaks with the relatives of Korean victims and South Korean officials at the site of former Fourth Souai Dormitory for the mine workers from the Korean Peninsula, after a memorial service in Sado, Niigata prefecture, Japan, Monday, Nov. 25, 2024, a day after boycotting a memorial organized by Japanese officials. The black banner reads "A memorial service for Korean forced laborer victims at Sado Mine." (AP Photo/Eugene Hoshiko)

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Relatives of Korean victims and South Korean officials offer a prayer during a memorial service at the site of former Fourth Souai Dormitory for the mine workers from the Korean Peninsula, in Sado, Niigata prefecture, Japan, Monday, Nov. 25, 2024, a day after boycotting a memorial organized by Japanese officials. The black banner reads "A memorial service for Korean forced laborer victims at Sado Mine." (AP Photo/Eugene Hoshiko)

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Relatives of Korean victims and South Korean officials offer a prayer during a memorial service at the site of former Fourth Souai Dormitory for the mine workers from the Korean Peninsula, in Sado, Niigata prefecture, Japan, Monday, Nov. 25, 2024, a day after boycotting a memorial organized by Japanese officials. (AP Photo/Eugene Hoshiko)

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South Korean Ambassador to Japan Park Cheol-hee, bottom left, leaves after a memorial service with the relatives of Korean victims and South Korean officials at the site of former Fourth Souai Dormitory for the mine workers from the Korean Peninsula, in Sado, Niigata prefecture, Japan, Monday, Nov. 25, 2024, a day after boycotting a memorial organized by Japanese officials. (AP Photo/Eugene Hoshiko)

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Offering by the relatives of Korean victims and South Korean officials are seen at an alter after a memorial service at the site of former Fourth Souai Dormitory for the mine workers from the Korean Peninsula, in Sado, Niigata prefecture, Japan, Monday, Nov. 25, 2024, a day after boycotting a memorial organized by Japanese officials. (AP Photo/Eugene Hoshiko)

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Relatives of Korean victims and South Korean officials offer a prayer during a memorial service at the site of former Fourth Souai Dormitory for the mine workers from the Korean Peninsula, in Sado, Niigata prefecture, Japan, Monday, Nov. 25, 2024, a day after boycotting a memorial organized by Japanese officials. The black banner reads "A memorial service for Korean forced laborer victims at Sado Mine." (AP Photo/Eugene Hoshiko)

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