A military court on Friday convicted a Russian officer of providing the CIA with secret information on Russia's new intercontinental ballistic missiles and sentenced him to 13 years in prison.
Lt. Col. Vladimir Nesterets pleaded guilty to passing on classified information in exchange for money, the Federal Security Service said.
The agency said Nesterets committed treason while he worked as a senior engineer at the Plesetsk launch pad in northwestern Russia, a facility the military uses to launch satellites and test its new missile systems.
The security service's terse statement did not say when Nesterets had been arrested or give any further details about his case.
RIA-Novosti quoted the officer's wife, Irina, as saying she could not understand the guilty plea because her husband had told her he did nothing wrong and had not betrayed his country.
The conviction comes amid growing tension in U.S.-Russian relations, despite President Barack Obama's efforts to overcome strains that had developed during the previous U.S. administration.
Relations between Moscow and Washington have worsened over a new U.S.-led missile defense system being developed by NATO around Europe, and Russia's teaming with China to block a UN Security Council resolution that would have urged Syrian President Bashar Assad to step down.
Prime Minister Vladimir Putin has been increasingly eager to challenge the United States as he campaigns to reclaim the presidency in next month's election. He has accused Washington of driving the mass pro-democracy protests in an effort to weaken Russia.
Political scientist Pavel Salin said the case against Nesterets should be seen in the context of the presidential election.
"The Russian authorities are pushing the idea of Russia as a besieged fortress, and in order to buttress this idea, they need big, scandalous cases to show that the Western special services are active on the country's territory," Salin said.
Earlier this week, Putin's protege, President Dmitry Medvedev, praised the Federal Security Service for exposing 41 foreign intelligence officers and 158 of their agents last year.