South Korea's top diplomat said Thursday that Japan would "bear the cost" of tarnishing its international image and reputation if it continues to renege on its commitments to address the historical issue of forcibly mobilizing Korean workers during its colonial rule from 1910 to 1945.

Foreign Minister Cho Tae-yul publicly criticized Japan for failing to honor its pledge to hold a memorial ceremony to sincerely honor the sacrifices of Korean forced laborers at the Sado Gold Mine in return for South Korea’s consent to inscribe the site to the UNESCO World Heritage list in July this year.

"I was surprised because what (Japan) presented fell short of even the agreed-upon standards," Cho told lawmakers during an emergency briefing to the National Assembly’s Foreign Affairs and Unification Committee, convened to address South Korea's last-minute decision to boycott Japan's memorial ceremony on Sunday.

Cho further explained that "The content of the memorial address fell far short in terms of addressing the nature of forced mobilization," referring to the speech delivered by Akiko Ikuina, a parliamentary vice minister at Japan’s Foreign Ministry and the chief government delegate for the event.

Cho likened Japan's unfulfilled promise to a "bounced check," and denounced Tokyo for "honoring its commitment in name only."

"Even if we respond firmly, I believe the greater issue lies in the fact that Japan must change its stance," Cho said when asked whether South Korea would adopt a tougher approach to Japan's failure to fulfill its commitments.

"There are responsibilities that we must bear and those that Japan must shoulder. However, if Japan fails to faithfully carry out (its commitment) in this manner, I believe it will have to bear the costs to its image and reputation in the international community as a result," Cho added.

The Japanese delegation pledged to honor its commitments, emphasizing "sincerely remembering all the workers at the Sado Island Gold Mines, especially those from the Korean Peninsula," and vowed to hold a memorial event for all the workers annually at the site during the 46th Session of UNESCO's World Heritage Committee in July, where the inscription of the Sado Island Gold Mines was discussed

Cho stated that Seoul and Tokyo failed to bridge their differences until the eve of the ceremony, despite being engaged in months of talks where the Yoon Suk Yeol administration had consistently emphasized the need for a "sincere memorial ceremony."

"I would like to emphasize that the decision not to attend the memorial ceremony was an unavoidable one, made under the judgment that there were no other options in a situation where our legitimate demands were not accepted (by Japan)," Cho said during the Assembly's televised briefing.

"This issue is a matter of judgment on whether Japan has properly fulfilled the commitments made to South Korea and the international community through the agreement concluded last July."

Cho acknowledged that Japan failed to adequately address the forced nature of Korean workers in its exhibition, titled "The Life of Mine Workers, Including Those from the Korean Peninsula." The exhibition, set up at the Aikawa History Museum on Sado Island, was part of Japan's efforts to secure South Korea's consent to gain the UNESCO World Heritage status.

"The exhibition focuses more on the harsh working conditions rather than on the forced labor itself," Cho said.

Cho affirmed that the Yoon government would continue to address Japan's failure to fulfill its commitments made during the July UNESCO session, raising the issue through the World Heritage Committee under UNESCO, and urging Japan's compliance.

The Japan-hosted memorial ceremony has drawn sharp criticism from lawmakers of both ruling and opposition parties.

Rep. Kim Gi-hyeon of the ruling People Power Party said, "Japan deserves condemnation for undermining its own national stature and dignity, which it should uphold as a responsible member of the international community."

Rep. Lee Jae-jung of the main opposition Democratic Party of Korea condemned the Japan-hosted memorial ceremony, calling it a "disgraceful diplomatic tragedy."

More than 1,500 Koreans were forced to work at Sado mines under harsh conditions and without proper compensation toward the end of Japanese colonial rule, according to a joint report in 2022 by the Korean Center for Historical Truth and Justice in Seoul and the Network for Research on Forced Labor Mobilization in Kobe.