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 for UNESCO confirmed their presence on the tentative list to NK News, but declined to comment on North Korea’s objections.

Whether or not the sites will make it onto the final list will be decided at the start of July. They have already been recommended by the International Council on Monuments and Sites (ICOMOS), an group of interdisciplinary experts who vet the candidates.

“ICOMOS recommends that the Sites of Japan’s Meiji Industrial Revolution: Iron and Steel, Shipbuilding and Coal Mining, Japan, be inscribed,” their 2015 report reads.

The July decision will be the culmination of a six-year process, with the most recent recommendation coming in March this year. The DPRK’s latest complaint with the procedure comes amidst recent Chongryon arrests in Japan.

The detentions appear to have struck a nerve in North Korea, with state media criticizing the arrests on a daily basis. According the NK News KCNA Watch tool, KCNA published more five articles on the topic in the last two days.

Whether or not the sides should be added to list of UNESCO World Heritage sites appears to a contentious issue on both sides of the 38^th Parallel.

“If you look at their tentative list on UNESCO, it doesn’t include spinning mill/factory, but only coal mine, steel factory and shipyard which produces the essential elements for the preparation of war,” Kim Seung-eun, senior researcher at the Center for Historical Truth and Justice told NK News.

“Historically, back then, North had more factories or industrial facilities than South. If the locals were called upon for the forced labor, it is natural to think that more locals have to suffer and share the memory of despair,” Kim added.

Additional reporting by Thomas Grevedon and JH Ahn

Featured image: “Battle-Ship Island Nagasaki Japan” by Flickr user: kntrty