MOSCOW (Reuters) - Russia has charged former U.S. Marine Paul Whelan with espionage, Interfax news agency reported on Thursday, citing what it described as an informed source.
Russia's FSB security service detained Whelan on Dec. 28 in Moscow on suspicion of spying but did not disclose the nature of his alleged espionage activities.
Reuters could not independently verify the Interfax report.
U.S. Secretary of State Mike Pompeo said on Wednesday that the United States wants an explanation for why Russia detained Whelan on spying charges and will demand his immediate return if it determines his detention is inappropriate.
Whelan's family has said that he was visiting Moscow for the wedding of a retired Marine and is innocent of the espionage charges against him.
Under Russian law, espionage can carry sentences of between 10 and 20 years in prison.
(Reporting by Gabrielle Tétrault-Farber; Editing by Andrew Heavens)