MOSCOW, April 13. /TASS/. US Ambassador to Russia John Sullivan has not been allowed into the Moscow City Court to attend a hearing in the case of US national Paul Whelan charged with espionage due to coronavirus-related restrictions, the court’s press service told TASS.

"Special regulations have been put in place due to coronavirus, and only participants in the trial are allowed to attend court hearings. May we also remind you that the trial is held behind closed doors because of its classified nature," the press service said.

Sullivan tried to get inside the court building to see Whelan before the hearing.

Paul Whelan, an American citizen, who also holds British, Canadian and Irish passports, was detained by the Russian Federal Security Service (FSB) on December 28, 2018, in Moscow while on a spy mission. A criminal investigation was launched against him on espionage charges carrying a punishment of up to 20 years behind bars. He pled not guilty, and his defense attorneys insist that the case has been trumped up.