The government of Nanjing, China, plans to register facilities that the Imperial Japanese Army used as military brothels as cultural properties, city officials said Friday.

The plan, which according to Chinese officials has not yet been finalized, is regarded as part of an anti-Japan propaganda campaign that has accelerated since China and South Korea all but formed a united front over issues concerning Japan’s wartime aggression, following recent developments in Japan.

According to local media reports in the capital of Jiangsu province, several wooden buildings once used as brothels are still standing in an area of about 4,800 sq. meters. The area used to be as large as 8,000 sq. meters during the war and included nearby stores, the reports said.

Experts say they consider the area to be Asia’s largest remaining site for the brothels, known euphemistically in Japan as “comfort stations.”

The Nanjing sites are said to have housed women from the Korean Peninsula and Japan who were forced to provide sex for Japanese soldiers.