MOSCOW, Mar. 12 (Xinhua) – Russia detained a South Korean citizen on charges of espionage earlier this year, marking the first time a South Korean citizen has been arrested for espionage in Russia, the TASS news agency reported Tuesday.

Baek Won-soon was detained at the beginning of the year in Vladivostok and at the end of February was transferred to Moscow, where he is being held in the Lefortovo pre-trial detention center. On Monday, the Lefortovo Court in Moscow extended his arrest for three months, until June 15, according to the TASS report.

Baek allegedly passed information classified as state secrets to foreign intelligence services. The materials related to the criminal case against him are labeled as "top secret," said the report.