Authorities in Estonia have arrested what is believed to be an agent of the Russian Federal Security Service, planning to commit computer-related crime in the country, according to Estonian media reports.
Last weekend, Estonian authorities picked up the 20-year-old man as he was leaving the city of Narva. They claim that he was about to return to Russia with confidential information.
Investigators suggested that he was prepared to commit "non-violent acts of an alien directed against the Republic of Estonia" and "a computer crime".
This information was revealed by Estonian FireEye analyst Patrik Maldre, who translated the account of the arrest in Estonian newspaper Postimees.
Russia has been caught-up in a string of cyber-related incidents in recent years, including a cyber attack on the electrical infrastructure of neighbouring Ukraine, and allegations that it has exploited social media in a bid to influence elections outside of Russia.
And as long ago as 2007, Estonia suffered from a catastrophic denial-of-service attack initiated by cyber criminals traced to Russia.
Speaking to Estonian public broadcaster ERR, state prosecutor Inna Ombler said: "Acting against the Republic of Estonia as an agent of the special service of a foreign country is without a doubt a serious crime, and we will figure out all the essential facts as soon as possible.
The country has notified the appropriate Russian authorities, added Ombler. "Right now, we can say without releasing any details that greater damage was prevented."
"Russia's diplomatic institutions are keeping a close eye on the development of the situation," the embassy said. "Our consuls are ready to provide assistance to the Russian citizen when a request from him to this effect is received."
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