A Russian court extended Friday the pre-trial detention of U.S. journalist Evan Gershkovich by two more months until March 30.

Gershkovich, an American Wall Street Journal reporter, is being held in Moscow on espionage charges which he denies.

"The period of detention of Evan Gershkovich ... is extended by two months ... till March 30," the court said on Telegram.

Gershkovich, his employer and the U.S. government vehemently reject the spying charges, the first to be leveled against a foreign journalist since the Soviet era.

He was arrested during a reporting trip at the end of March last year in the Urals city of Yekaterinburg and could spend up to 20 years in prison if convicted.

The American, who previously worked for AFP, continued to report from Russia after the Kremlin launched its Ukraine offensive, despite many Western journalists leaving the country.

Russia claims it caught Gershkovich "red-handed," but has not provided any public evidence of the allegations it has made against him.

He has been held at Moscow's notorious Lefortovo prison.