North Korea lashed out via state media on Wednesday at possible Japanese candidates for UNESCO World Heritage sites, on the grounds they were built on Korean slave labor.

The article, featured by both the Rodong Sinmun and Korean Central News Agency (KCNA), takes aim at several industrial sites on the tentative UNESCO list.

“Among them are the Mitsubishi Shipyard and the Hashima Coal Mine where more than 57,000 Koreans were forced to do slave labor and met death,” the article reads.

While it is difficult to find the sites mentioned on the UNESCO website, a representative from Japan’s National Commission