Jailed American reporter Evan Gershkovich has appeared in a Moscow court to appeal against his detention on spying charges.

Dozens of journalists crowded together to catch a glimpse of the Wall Street Journal reporter, who is the first US correspondent since the Cold War to be detained in Russia on spying allegations.

Mr Gershkovich looked calm as he stood inside a glass cage, with US Ambassador Lynne Tracy in the room.

Russia’s Federal Security Service detained the 31-year-old in Yekaterinburg in March and accused him of trying to obtain classified information about a Russian arms factory.

Wall Street Journal reporter Evan Gershkovich is being held on spying charges (Alexander Zemlianichenko/AP)

Mr Gershkovich, his employer and the US government all deny he was involved in spying and have demanded his release.

Last week, the US government declared that he was “wrongfully detained” — a designation that means his case receives special attention from the State Department.

The Moscow City Court is considering a defence appeal against his detention on Tuesday.

Mr Gershkovich could face up to 20 years in prison if convicted. Russian lawyers have said past investigations into espionage cases took a year to 18 months, during which time he could have little contact with the outside world.

He has been held in Moscow’s Lefortovo prison, which dates from the Tsarist era, and has been a terrifying symbol of repression since Soviet times.

Mr Gershovich denies the charges (Alexander Zemlianichenko/AP)

The arrest came at a moment of bitter tensions between the West and Moscow over its invasion of Ukraine and as the Kremlin intensifies a crackdown on opposition activists, independent journalists and civil society groups.

The sweeping campaign of repression is unprecedented since the Soviet era. Activists say it often means the very profession of journalism is criminalised, along with the activities of ordinary Russians who oppose the war.

Last month, a Russian court convicted a father over social media posts critical of the war and sentenced him to two years in prison.

On Monday, a Russian court convicted top opposition div Vladimir Kara-Murza of treason for publicly denouncing the war and sentenced him to 25 years in prison.

The US has pressed Moscow to grant consular access to Mr Gershkovich.

On Monday, Ms Tracy said she visited Mr Gershkovich in prison for the first time since his detention. She said on Twitter that “he is in good health and remains strong”, reiterating a US call for his immediate release.

President Joe Biden spoke to Mr Geshkovich’s parents last week and again condemned his detention.

“We’re making it real clear that it’s totally illegal what’s happening, and we declared it so,” he said.

A top Russian diplomat said last week that Russia might be willing to discuss a potential prisoner swap with the US involving Mr Gershkovich after his trial. That means any exchange is unlikely to happen any time soon.

In December, American basketball star Brittney Griner was exchanged for Russian arms dealer Viktor Bout following her trial and conviction on drug possession charges. She had been sentenced to nine years in prison and ended up spending 10 months behind bars.

Another American, Michigan corporate security executive Paul Whelan, has been imprisoned in Russia since December 2018 on espionage charges, which his family and the US government have called baseless.