Greek authorities have arrested a 59-year-old man in the port city of Alexandroupolis on suspicion of espionage for Russia, according to a police statement released Tuesday.
The suspect, a Greek national of Georgian descent, was reportedly caught photographing and filming military supply convoys.
Police say he confessed to collecting the images and sending them through an encrypted app to an unidentified contact.
Officials believe the men were targeting convoys transporting military aid to Ukraine.
Sources told AFP that videos found on his mobile phone confirmed the surveillance activities.
The man, who described himself as a house painter, allegedly served in the Russian military in his youth.
Investigators suspect he was recruited by Russia’s GRU intelligence agency via a Georgian intermediary based in Lithuania with links to organised crime.
Despite Greece’s historical ties to Russia, the country has aligned itself with NATO in supporting Ukraine since the war began. The suspect appeared before a magistrate on Friday as investigations continue.