US Secretary of State Anthony Blinken urged US citizens to leave Russia immediately.

The warning applies to US citizens residing in or planning to travel to Russia.

"We are deeply concerned by the Russian announcement that an American journalist has been arrested. The highest priority of the State Department is the safety of citizens abroad," Blinken wrote on his Twitter account.

The Russian Security Service (FSB) detained Evan Gershkovich, a journalist of the American newspaper "Wall Street Journal", on charges of espionage.

According to the FSB, Gershkovich "on the instructions of the American side, collected information that is treated as a state secret about the activities of one of the enterprises of the Russian military-industrial complex."

The journalist, who was arrested in the Ural city of Yekaterinburg, faces up to 20 years in prison.