Three people have been convicted in recent months by Estonian courts on charges of spying for Russia, according to the country's state prosecutor's office, the Interfax news agency reported Tuesday.
Last week an Estonian national, Maxim Gruzdev, was sentenced to four years in prison on espionage charges.
Gruzdev was arrested in October. He was allegedly providing information on the activities of KAPO, Estonia's counterintelligence service, to the Russian secret services.
Two more people were sentenced to jail terms for espionage in October. Alexander Rudnev, a 21-year-old Estonian citizen, was sentenced to two years in prison. Pavel Romanov, 42, was sentenced to four years and 10 months in prison.