Russia’s top security agency says a reporter for the Wall Street Journal has been arrested on espionage charges.

The Federal Security Service (FSB), the top domestic security and counterintelligence agency that is the top successor agency to the Soviet era KGB, said Thursday that Evan Gershkovich was detained in the Ural Mountains city of Yekaterinburg while allegedly trying to obtain classified information.

Gershkovich is the first reporter for an American news outlet to be arrested on espionage charges in Russia since the Cold War. His arrest comes amid the bitter tensions between Moscow and Washington over the fighting in Ukraine.

The security service alleged that Gershkovich “was acting on the U.S. orders to collect information about the activities of one of the enterprises of the Russian military industrial complex that constitutes a state secret.”

The FSB didn’t say when the arrest took place. Gershkovich could face up to 20 years in prison if convicted of espionage.

Gershkovich covers Russia and Ukraine as a correspondent in the Wall Street Journal's Moscow bureau. The FSB noted that he had accreditation from the Russian Foreign Ministry to work as a journalist.

His last report from Moscow, published earlier this week, focused on the Russian economy's slowdown amid Western sanctions imposed when Russian troops entered Ukraine last year.