Putin made his first official visit to the islands, administered by Russia since 1945, on Aug 13, prompting Japan to summon Russia’s ambassador – a move then reciprocated by Moscow.
Putin went there after visiting the nearby Russian island of Sakhalin, where Russia’s navy was conducting drills.
His visit was the first trip to the islands by a Russian president since Dmitry Medvedev in 2010.
After Putin’s stop, Japanese Prime Minister Sanae Takaichi said the islands “are an inherent part of Japan’s territory, both historically and under international law”.
Ties between Japan and Russia have worsened since the full-scale conflict in Ukraine began in 2022.
Japan has joined other G7 countries in sanctioning Moscow and aiding Kyiv.
Ukraine, like the United States, recognises Japanese sovereignty over the disputed islands.
Analysts said Putin’s visit to the Kurils could have been aimed at warning Japan against deepening its support for Ukraine – potentially including the direct supply of Patriot missiles – and against closer cooperation with NATO.
Japan currently provides only non-lethal defence aid to Ukraine.
While Japan has eased restrictions on defence exports in recent years, it is still barred from supplying lethal military equipment directly to a country at war.
