(NewsNation) — Journalists and supporters around the world are calling for the release of a reporter detained in Russia on accusations of spying.

Russian journalists are among those calling on the Kremlin to release an American journalist who they say has been wrongfully detained.

More than 200 journalists signed an open letter to Moscow, demanding the release of Evan Gershkovich, the Wall Street Journal reporter who was detained in Russia last week and is now being accused of spying for the U.S. government.

It’s the first time since the Cold War that a U.S. correspondent has been detained for alleged spying.

The Russian foreign ministry alleged Thursday that the “hype” in the U.S. is a hopeless and senseless attempt to pressure Russian authorities and the Moscow court hearing Gershkovich’s case.

A childhood friend told NewsNation that Gershkovich is friendly man who connects easily with others.

“He’s the guy that you introduced to your friend, and five minutes later, your turn around, and they’re laughing and talking, you know, really deeply about something and you can’t believe why or how,” Thatcher Foster said.

He said the journalist’s friends and family have received an outpouring of support and are working to keep Gershkovich’s name in the headlines as they continue to hope for his release.

“You just don’t always have the concept of how many people he touches, and how much he means to so many different people. And I think that, to me, is what fills us all with pride,” Foster said.

Gershkovich was arrested east of Moscow last week and is being held behind bars at Lefortovo Prison, a site used for torture and executions during Joseph Stalin’s Great Purge. It was once the KGB’s main detention facility, the same place where former U.S. Marine Paul Whelan was held for two years.

“They make the psychological content — of keeping you alone and isolated in a metal box that’s maybe 7 by 12 feet — really intense,” said CBS News Moscow correspondent Jonathan Sanders. “You get fed through a slot. It’s really impersonal. You can’t knock on the walls to talk to somebody in code, because the walls are too thick. You might as well be on the dark side of the moon.”

Russian authorities said they caught Gershkovich “red-handed” using his journalistic status as a cover for illegal actions, accusing him of working to obtain classified information about a Russian arms factory. But Gershkovich’s employer has denied the allegations.

U.S. authorities have condemned his arrest.

“In my own mind, there’s no doubt he’s being wrongfully detained,” Secretary of State Antony Blinken said.

Public outcry has been swift, with hundreds of journalists signing an open petition demanding he be freed and hashtags supporting Gershkovich’s cause.

“I am certain that as we’re having our interview now, there are negotiations that are taking place in terms of a prisoner swap,” said Dani Belo, a professor of international relations at Webster University.

A Moscow court will hear an appeal on April 18 that could decide whether Gershkovich is held or granted bail. Lawyers representing Gershkovich had a meeting with him on Tuesday. It’s been reported he is in good health and grateful for the outpouring of support from around the world.