UNESCO should take into account opposing views in its heritage registration process in light of criticism leveled by Japan about its inscription of China's "Documents of Nanjing Massacre" in the Memory of the World project, a report issued by its advisory committee says.

Japan is urging the U.N. Educational, Scientific and Cultural Organization to improve the transparency and fairness of the screening and registration process, after discussions on the 2015 inclusion of China's documents were conducted behind closed doors by experts, just like the other registrations.

UNESCO will make a final decision on recommendations to change the process as early as this summer after hearing the opinions of member countries at an executive board meeting starting Wednesday.