Moscow | US Ambassador Lynne Tracy on Monday was allowed to visit Wall Street Journal reporter Evan Gershkovich, who has been behind bars in Russia since March on charges of espionage.

Tracy last visited Gershkovich in April. The US Embassy confirmed Monday's visit but did not immediately provide more information.

The 31-year-old US citizen was arrested in the city of Yekaterinburg while on a reporting trip to Russia. A Moscow court last week upheld a ruling to keep him in custody until Aug 30.

Gershkovich and his employer denied the allegations, and the US government declared him to be wrongfully detained. His arrest rattled journalists in Russia where authorities have not provided any evidence to support the espionage charges.

Gershkovich is being held at Moscow's Lefortovo prison, notorious for its harsh conditions.

He is the first American reporter to face espionage charges in Russia since September 1986, when Nicholas Daniloff, a Moscow correspondent for U.S. News and World Report, was arrested by the KGB. Daniloff was released 20 days later in a swap for an employee of the Soviet Union's U.N. mission who was arrested by the FBI, also on spying charges.