Russia said Monday it had detained a Japanese diplomat based in the eastern city of Vladivostok for carrying out espionage-related work and declared the official person non grata, news agencies reported.

"A Japanese diplomat was detained red-handed while receiving classified information, in exchange for money, about Russia's cooperation with another country in the Asia-Pacific region," the FSB security service said in a statement, carried by Russian news agencies.

The diplomat had also been soliciting information about "the impact of Western sanctions" on the eastern Primorsky region, the FSB said, according to news agencies.

Russia's foreign ministry said in a statement the diplomat was ordered to leave the country within 48 hours.

The FSB said it had lodged a protest with Tokyo through diplomatic channels and declared the diplomat identified as consulate general in Vladivostok, Motoki Tatsunori, persona non grata, the news agencies reported.

The FSB distributed a short video it said showed the diplomat acknowledging that he had violated Russian laws.

Russia considers Japan to be a "hostile" country, a designation it shares with all EU countries, the United States and allies including Britain and Australia.

Moscow and Tokyo have traded tit-for-tat sanctions and expulsions of diplomats since February 24 when Vladimir Putin launched what the Kremlin calls its "special military operation" in Ukraine.

Tokyo had complex relations with Moscow before the Ukrainian invasion and the two sides have yet to sign a post-World War II peace treaty.

Attempts to do so have been hampered by a long-running dispute over islands controlled by Russia, which calls them the Kurils.