A former Russian diplomat has been sentenced to 12 years in a high-security penal colony after being convicted of passing state secrets to the United States, which allegedly happened during his stint as an assistant to Russia's consulate general in Houston, where he worked between 2014 and 2017.

The Federal Security Service (FSB) announced Friday that 38-year old Arseniy Konovalov has been found guilty of treason. He was detained in March last year on suspicion of providing classified information to American intelligence, and the newly released video of the moment he was detained by the Russian security service while inside a vehicle upon his return to Russia has gone viral. He has a look of utter shock and horror on his face upon realizing what was happening.

The FSB in its statement alleged that “AS Konovalov, an employee of the Russian foreign ministry, during a long-term foreign assignment in the United States, proactively transferred secret information to American intelligence for money.”

The video release further showed Konovalov placed in a holding cage at Moscow's Lefortovo district court by masked officers after being taken from the vehicle.

On top of the sizeable prison sentence, the court also fined Konovalov 100,000 roubles. The security service did not specify the nature of the information which was allegedly handed over to the US side, nor did it make any supposed evidence public. 

US officials have also not commented on or confirmed the case, but there has been speculation on Russian Telegram channels that Konovalov was recruited by the CIA at some point.

There are reports that espionage and treason investigations and cases overseen by Russian authorities have jumped significantly since the start of the Ukraine war, which is about to reach completion of its fourth year.

Watch: The diplomat's eyes get big, a shocked and anxious look on his face, at the moment one FSB officer holds up an identifying badge and the others grab him from behind...

Certainly there's been an intelligence-driven 'dirty war' happening with intensity behind the scenes both in Russia and Europe, as each rival side tries to gain an informational edge in the context of the NATO vs. Moscow stand-off.

There have also over several years been a number of American travelers and even journalists arrested in Russia on allegations of espionage - though Washington has consistently deemed these 'wrongful detentions'.