A court in Moscow has sentenced a former defense factory chief from Ukraine to six years in prison on espionage charges, a verdict that comes amid continuing tensions in Russia-Ukraine ties.

The Moscow City Court on Wednesday found Yuri Soloshenko, the 73-year-old former head of the Znamya electronics plant in Poltava, guilty of spying.

The Federal Security Service, Russia's main domestic security agency known under the Russian acronym FSB, said in a statement that Soloshenko was arrested in Moscow in August 2014 while trying to buy secret components for the S-300 air defense missile system. Both Russia and Ukraine have the Soviet-designed weapon in their arsenals.

Russia and Ukraine have remained locked in a tug-of-war following Moscow's annexation of Ukraine's Crimean Peninsula and support for insurgents in eastern Ukraine.