Lithuanian prosecutors say they have charged a Russian citizen with spying for Russia's Federal Security Service, the top successor to the KGB.

The Prosecutor General's Office says the 39-year-old man who was identified as a "high ranking" agent for Russia's domestic security agency, is also suspected of falsification of documents, use of false documents and multiple illegal border crossings. His name was not disclosed.

The office said Friday he was detained last year when traveling by train from Russia's Baltic Sea exclave of Kaliningrad to Belarus via Lithuania. The exclave is wedged between the small Baltic country and Poland.

No date for a trial was immediately announced. If convicted, he faces up to 15 years in prison.