A number of Russian scientists have been arrested and charged with treason in recent years for allegedly handing sensitive material to foreigners.
State prosecutors have charged a prominent Russian scientist with treason after accusing him of passing state secrets to China, his lawyer said on Monday, adding that his client could serve up to 20 years in prison if found guilty.
Valery Mitko, president of the Arctic Academy of Sciences in St. Petersburg, has been under house arrest since authorities charged him with high treason in February.
Ivan Pavlov, his lawyer, said the 78-year-old academic travelled to China twice a year to speak as a guest lecturer and denied handing state secrets to the Chinese authorities.
Mitko did travel to China with documents for his lectures, but these contained academic and open source information only, Pavlov said.
"There were no state secrets in there at all. We consider these accusations to be absurd," Pavlov said, saying he hoped the case would be dismissed before trial.
Sources told Russian news agencies TASS and Interfax that Mitko has been accused of having given China information pertaining to methods used to detect submarines.
Mitko is also a former navy captain and served in the Pacific Fleet, according to an association of Russian navy veterans.
A number of Russian scientists have been arrested and charged with treason in recent years for allegedly handing sensitive material to foreigners. Critics of the Kremlin say the arrests often stem from unfounded paranoia.
Russia is an important player in the Arctic region and has been building up its military presence there as climate change has opened up the resource-rich region.
China, which defines itself as a "near-Arctic state", is seeking better access to untapped resources and faster trade through the Northern Sea Route. It has also invested more in Arctic research.
Despite the misgivings of some nationalist politicians, Russia has increasingly prioritised closer ties with China, especially since its relations with the West collapsed in 2014 over its annexation of Crimea from Ukraine.