Russia summoned Japan’s ambassador to Moscow on Tuesday amid a diplomatic dispute over President Vladimir Putin’s visit last week to the Russian-held Kuril Islands, which Japan claims as its Northern Territories.
The islands were seized by the Soviet Union in 1945, after which their Japanese population was expelled. The territorial dispute has remained a longstanding source of tension between Moscow and Tokyo.
Putin, 73, visited the islands Thursday, prompting Japan to summon Russia’s ambassador in protest.
It was the first visit to the disputed territories by a Russian president since Dmitry Medvedev traveled there in 2010. Medvedev served as president from 2008 to 2012 while Putin was prime minister.
Japanese Prime Minister Sanae Takaichi said the islands “are an inherent part of Japan’s territory, both historically and under international law.”
Russia said Monday that it had summoned Japanese Ambassador Akira Muto over the dispute.
Russian Foreign Minister Sergei Lavrov accused Tokyo of having “crossed the line of decency.”
Muto did not initially respond to the summons.
“We were told either that he was not in Moscow or that he was unwell. We did not quite understand the situation,” Lavrov said.
Russian Foreign Ministry spokeswoman Maria Zakharova later told state news agency TASS that after Lavrov’s remarks, the ambassador had “suddenly started feeling better” and would attend Tuesday.
Japanese public broadcaster NHK reported that Muto had initially held back because of concerns that Russia would unilaterally dominate the discussions and prevent a balanced exchange.
Tokyo later decided to respond to the summons following internal deliberations, NHK reported, citing unnamed sources.
Relations between Japan and Russia have deteriorated further since Russia launched its full-scale war against Ukraine in 2022.
Japan has joined other G7 countries in imposing sanctions on Russia and has provided financial assistance and non-lethal defense aid to Kyiv.
Ukraine, like Washington, recognizes Japanese sovereignty over the disputed islands.
Japan also indirectly supports Ukraine’s air defense by exporting domestically produced Patriot interceptor missiles to the U.S., helping replenish American stockpiles reduced by military assistance to Kyiv.
Analysts said Putin’s visit to the Kuril Islands could have been intended as a warning to Japan against deepening its support for Ukraine, including potentially supplying Patriot missiles directly or increasing cooperation with NATO.
Japan has eased some restrictions on defense exports in recent years but remains unable to directly provide lethal military equipment to a country at war, including Ukraine.
The territorial dispute remains unresolved as Moscow and Tokyo continue to clash over the islands and Japan’s support for Kyiv.