A group of former and current Diet members demanded Friday that Japan Post issue stamp sheets featuring images of three sets of islands embroiled in territorial disputes.

The territories in question are Takeshima Island off Shimane Prefecture, which is also claimed by South Korea, which calls it Tok-do, four islands off northeast Hokkaido that are held by Russia, and the Senkaku Islands in the East China Sea, which are claimed by China and Taiwan as the Diaoyu and Tiaoyutai isles, respectively.

The 13-member group, headed by House of Representatives member Masahiro Morioka, said its action is aimed at showing Japan's determination to protect its own territories. All are members of the Liberal Democratic Party.

Fearing that the stamp sheet issue could fuel ongoing territorial rows with the other parties to the disputes, Japan Post refrained from making any immediate decision. It promised the group that it would explain its conclusion later in writing, a Japan Post official said.

Japan Post offers a service whereby it prints stamp sheets that come with any photo provided by customers. The group asked it to issue a total of 150 sheets, each holding 10 stamps.