Japan protests dessert to be served to North Korean leader Kim Jong Un The cake is planned to have a picture of a unified Korean peninsula.

Japan has lodged a complaint over the dessert planned for North Korean leader Kim Jong Un when he meets South Korea's president this week.

After South Korea announced it would dish out a mango mousse cake decorated with a garnish showing the shape of a unified Korean peninsula, Japan objected to the map’s inclusion of disputed islands.

Japan filed a protest on Tuesday with South Korea, a spokesperson for Japan’s Ministry of Foreign Affairs, Natsuko Sakata, told ABC News.

The disputed island grouping is located in the sea between South Korea and Japan; they’re known in South Korea as Dokdo and in Japan as Takeshima. South Korea controls the islands, but Japan also claims them. North Korea has said it considers them Korean.

A map of a unified Korea that features the disputed islands will also appear on chairs that will be used by Kim and South Korea’s president, Moon Jae-in.

"Nations have no other choice but to react this way because it is an ongoing territorial dispute," David Satterwhite, an expert on Korean politics at Temple University Japan, in Tokyo, told ABC News. "Japan has to say, 'Wait a minute, that’s Japanese territory.'"

Earlier this year, South Korea dropped plans to show the islands on a flag the unified Korea team used at the Winter Olympics in Pyeongchang after Tokyo complained, Agence France-Presse reported. The French news agency said a flag at a practice game had featured the islands.

ABC News' Anthony Trotter reported from Tokyo.