A former U.S. Marine held in a Russian prison for more than a year pleaded not guilty to espionage charges Monday, and his trial is set to begin next week after being delayed further due to the country’s strict coronavirus lockdown measures.

Paul Whelan, 50, appeared to be in good spirits at the arraignment hearing Monday where prosecutors read the charges against him, according to a report by CBS News.

The first witnesses in the case will be called next week, lawyers said, and Whelan faces 20 years in prison if convicted.

“Paul said that he believes he was framed and that [the case] was a provocation against him,” said defense attorney Olga Karlova.

Jailed since 2018

Whelan has been jailed at the notorious Lefortovo Prison since his arrest at a Moscow hotel in December 2018. Russian police accused Whelan of spying, saying he was “caught red-handed” with a USB flash drive that contained government secrets.

At the time, Whelan was the global security director for Michigan-based automotive components supplier BorgWarner, CBS reports.

When authorities burst into his hotel suite, Whelan explained that he was in Russia to attend a wedding, and that he took the device from an acquaintance believing it only contained vacation photos.

His trial has been declared classified, and even Monday’s hearing was held behind closed doors, CBS reports. U.S. Ambassador to Russia John Sullivan tried to attend the arraignment but was not allowed inside.

The ambassador has been especially critical about Whelan’s treatment by Russian authorities and called the trial a “mockery of justice.”

In a statement Monday on the former soldier's condition, Sullivan said Whelan "needs medical care and he needs to go home."

Whelan has been placed in solitary confinement and has not been permitted to contact family members during his entire time behind bars.

Whelan’s attorneys also argued Monday that he suffers from several health issues, including a hernia, and pushed for Whelan to be seen by a doctor from the U.S. Embassy in Moscow, CBS reported citing Russia’s Interfax news agency.

After 14 years with the Marine Corps, Whelan was discharged in 2008 for bad conduct, according to the military.

Another Marine in custody

Another former U.S. Marine from Texas is also facing charges in Russia after he was accused of assaulting two Moscow police officers who arrested him late last year.

After a night of drinking, Trevor Reed, 28, reportedly grabbed an officer’s arm and allegedly struck another officer as he was being transported to the station, causing minor injuries.

Despite the minor nature of the charges, Reed still faces 10 years in prison in the matter.

His girlfriend said he was interrogated by members of Russia’s Federal Security Agency, or FSB, the country’s most powerful security body, according to The New York Times.

The detentions of both men could be intended to create leverage for a potential prisoner exchange between Russia and the United States, The Times reports.

U.S. officials have heeded the call of family members and repeatedly called on Russia to free them.

In January, following international pressure, Russian President Vladimir Putin pardoned an American Israeli woman who was sentenced to 7½ years in prison after a few grams of marijuana was found in her luggage.