WikiLeaks founder Julian Assange is so sick, he could die in prison if he does not get urgent medical care, according to an open letter sent Monday to British authorities.

More than 60 doctors wrote to UK Home Secretary Priti Patel to express “serious concerns” about Assange’s fitness to stand trial as he fights extradition to the US on espionage charges.

“It is our opinion that Mr. Assange requires urgent expert medical assessment of both his physical and psychological state of health,” wrote the doctors, from the UK, Australia, Europe and Sri Lanka.

“Were such urgent assessment and treatment not to take place, we have real concerns, on the evidence currently available, that Mr. Assange could die in prison.

“The medical situation is thereby urgent. There is no time to lose,” they wrote.

The letter says that Assange, 48, suffers from psychological problems including “major depression,” as well as dental issues and a serious shoulder ailment. He also shows the “symptoms of a torture victim,” the letter claims.

Assange is currently in Belmarsh prison on the outskirts of London serving a 50-week sentence for jumping bail as he also awaits his next extradition hearing in February.

US authorities have accused Assange of scheming with former Army intelligence analyst Chelsea Manning to hack a password for a classified government computer.

He could face up to 175 years in prison under the Espionage Act but claims he is a journalist entitled to First Amendment protection.