Jailed Wall Street Journal reporter Evan Gershkovich has been formally charged with espionage in Russia and has entered his official denial, Russian state news agency Tass reported Friday.

Tass said a law enforcement source informed the news agency that Russia’s Federal Security Service officially charged the American journalist with espionage. Tass did not specify if the action was taken during a court hearing.

Russian authorities arrested Gershkovich last week and accused him of trying to obtain classified information about a Russian arms factory. The Wall Street Journal has denied the accusations.

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