A Russian court has sentenced an elderly Ukrainian citizen who once served as director of a defence factory to six years in jail for espionage, a court spokesman said.

The classified case against Yury Soloshenko, 73, was brought by the federal security service (FSB) which accused him of trying to smuggle sensitive missile defence technology out of Russia.

“The court has sentenced him to six years in a strict penal colony,” a spokesman for the Moscow city court said.

Reports have identified Soloshenko as a pensioner from Ukraine’s eastern city of Poltava. Prison observer Zoya Svetova had said that investigators kept defence attorneys from working on the case against Soloshenko’s will.

Until 2010, Soloshenko was director of Znamya factory in the city which produced some components for old models of missile systems, including the BUK, the missile system that investigators say downed Malaysia Airlines flight MH17 last July over eastern Ukraine. The factory was declared bankrupt in 2012.

Soloshenko has been under arrest since his detention in August 2014 when the conflict between pro-Russian separatists and the Ukrainian government was at its height.

“Soloshenko was detained by FSB employees in August 2014 in Moscow when he was trying to illegally obtain secret components for S-300 (missile system),” said an FSB statement.

“He was acting in the interests of Ukrainian factory ‘Generator’ and the corporation ‘Sky of Ukraine’, and the parts he was going to buy were to be used to rebuild Ukraine’s missile defence,” it said.

Russia has seen an unprecedented number of espionage and treason cases reach trial over the past year, as the conflict in Ukraine has exacerbated already-strained relations with the west.

Just last week a court in western Russia sentenced a man to 12 years in prison for allegedly spying for Ukraine. In September, a former military intelligence engineer was sentenced to 14 years after soliciting a job with a Swedish organisation by email.