Russia has arrested a Japanese journalist on the far east island of Sakhalin and accused him of espionage, Moscow said on Tuesday.

Russia regards Japan as an “unfriendly” country because it has joined western sanctions over its war ⁠in Ukraine. Russia has arrested several citizens of “unfriendly” countries in recent years, accusing them of working for western intelligence services.

Russian foreign ministry spokeswoman Maria Zakharova identified the reporter as Yuki Imai from the Hokkaido Shimbun newspaper, saying Imai was accredited with the ministry but was accused of “conducting espionage activities on Russian territory”.

Japan’s embassy in Moscow told news agency Kyodo that the government was trying to ascertain the journalist’s reported detention.

Russia’s FSB security agency said a Japanese national, who it did not name, was arrested on Sakhalin and alleged he had worked for Japanese intelligence to collect information about Russia’s defences.

The FSB published a video showing masked officers storming a hotel room, pushing a man to the floor and handcuffing him. The man was flown to Moscow, where a court ordered he be held in pre-trial detention. It did not say when the arrest or court hearing occurred. The charges carry up to 20 years in prison.

Moscow and Tokyo have been locked in a territorial dispute for decades over the status of a string of islands in the Pacific Ocean, off the north-east coast of Japan and to the south-west of Russia’s Sakhalin region.

The FSB said it had “opened a criminal case against the Japanese national”, and that he had been placed in pre-trial detention, Russian news agencies reported, citing the agency.

Russian media reported he would remain in custody until 12 December.

“Attempts by Tokyo to use its correspondents in Russia … to gather information aimed at undermining the security of our state is regrettable,” Zakharova said, alleging this was “not an isolated case”.

The Kuril islands – which Japan calls the Northern Territories – have been under Russia’s control since the end of the second world war, when they were seized by the Soviet Union.

Russia’s president, Vladimir Putin, visited one of the disputed islands in August, causing an ​uproar in Japan. Tokyo has ‌said it would continue ​implementing sanctions against ​Russia and supporting Ukraine.

In 2023, US journalist Evan Gershkovich was arrested on espionage charges, later sentenced to 16 years in prison before being released in a 2024 prisoner swap.

With Agence France-Presse and Reuters