Former Russian President Dmitry Medvedev called Saturday on Japanese Prime Minister Fumio Kishida to die by "seppuku," a ritualistic suicide by disembowelment, after he and U.S. President Joe Biden warned Russia against using a nuclear weapon in Ukraine.The deputy chairman of Russia's Security Council called a joint statement in which the Japanese and U.S. leaders made the warning a "horrible shame" and said he would not "even comment on the paranoia regarding our state's nuclear plans," Tass news agency reported, citing his Telegram channel.Kishida can only "wash off" his shame by disembow…READ FULL ARTICLE