A Russian court said Thursday it has sentenced a man to 12 years in prison for allegedly spying for Ukraine, the latest in a spate of treason cases.

Russian Viktor Shur was on Wednesday found guilty by a regional court in Bryansk, on the border with Ukraine, of collecting secret information about defence facilities for the Ukrainian border service, the court said in a statement.

The court said Shur was detained by Russia's FSB intelligence service after crossing back into Russia in December 2014 and had confessed to treason during the trial.

Shur's trial was classified as secret and few other details of the case have emerged. The Bryansk court said the sentence had not yet entered into force pending an appeal.

Russian rights activist and journalist Zoya Svetova -- who met with Shur when he was detained in Moscow -- told AFP that he is aged around 60, had a residence permit in Ukraine and worked in architecture and antiques prior to his arrest.

Svetova dismissed the charges against Shur and said he told her that he had admitted to the accusations after Russian intelligence service said he would be treated leniently.

Svetova said that Shur's son, who lives in Kiev, had told her that his father had taken photographs of an abandoned aerodrome.

"He has obviously been deceived by the FSB," Svetova said.

The case against Shur is the latest in a raft of treason cases in Russia as the Ukraine crisis sent tensions with the West to their highest point since the end of the Cold War.

Moscow last month jailed a former military intelligence engineer for 14 years for allegedly passing on state secrets by sending his resume to a Swedish organisation.

Among other high-profile cases was that of a provincial housewife and mother of seven who phoned the Ukrainian embassy, worried that soldiers stationed in her town may be sent there. The charges were later dropped after a public outcry.