Russia''s Federal Security Service (FSB) reported on Monday the arrest of US citizen Paul Whelan under charges of espionage for which he could be sentenced to 10 to 20 years in prison.

Whelan was detained red handed last Friday 28, an FSB release indicates, though it does not elaborate further on details.

The Russian counter-espionage agency reported last February on the arrest of an Ukranian citizen in Simferopol, main city of Crimea, region that a following a referendum in March 2014 separated from Kiev and returned to Russian jurisdiction.