The presidential office responded to the controversy regarding the absence of the expression "forced labor" in an exhibition of Japan's Sado mines, which was recently named a UNESCO World Heritage site, saying the significance lies in the proactive steps taken by the Japanese government before the UNESCO listing.

In a phone call with KBS on Monday, an official from the top office said there is significance in the Japanese government taking initiatives, such as opening an exhibition hall on Korean laborers near the mine site, before the listing.

The official stressed that this was different from 2015, when Japan's Hashima Island was also registered as a UNESCO World Heritage site, but Tokyo failed to keep its promise of informing the public about its wartime forced labor of Koreans on the island.

The presidential official further explained that while the expression "forced mobilization" was not explicitly used in the exhibition, it did mention that Japan was involved in recruiting workers, and described the harsh reality of Korean workers.

Amid controversy that Japan was trying to whitewash the forced labor of Koreans at the Sado mines, it promised to install an exhibition near the site and hold an annual memorial service for former mine workers to get approval from South Korea, which is a member of the UNESCO World Heritage Committee.