WikiLeaks founder Julian Assange is suffering from "intense psychological trauma" in a British prison and should not be extradited to the United Sates to face a "politicized show trial," according to a UN human rights investigator.

UN torture expert Nils Melzer visited Assange in a high-security London prison on May 9 along with two medical experts, only to find the journalist under severe stress, agitated, and unable to cope with his complex legal case amid chronic anxiety, according to Reuters.

"Our finding was that Mr. Assange shows all the symptoms of a person who has been exposed to psychological torture for a prolonged period of time. The psychiatrist who accompanied my mission said that his state of health was critical," he told Reuters in an interview in Geneva, adding "But my understanding is that he has now been hospitalized and that he is not able to stand trial."

Melzer's comments come after Assange's attorney said he was unwell when he failed to show up for a London court hearing Thursday regarding his extradition battle. The 47-year-old is currently serving a 50-week sentence in the UK's Belmarsh jail for skipping bail. According to WikiLeaks he has been moved to the prison's health ward.

"Mr. Assange has been deliberately exposed, for a period of several years, to progressively severe forms of cruel, inhuman or degrading treatment or punishment, the cumulative effects of which can only be described as psychological torture," said Melzer.

Melzer, a Swiss law professor, did not say which judges or senior politicians had been defaming Assange, but that "dozens if not hundreds of individuals” had expressed themselves inappropriately."

"Here we are not speaking of prosecution but of persecution. That means that judicial power, institutions and proceedings are being deliberately abused for ulterior motives," he added.

British Foreign Minister Jeremy Hunt, in a tweet posted within minutes of Melzer’s statement, said: “This is wrong. Assange chose to hide in the embassy and was always free to leave and face justice. “The UN Special Rapporteur should allow British courts to make their judgments without his interference or inflammatory accusations,” he said. -Reuters

Assange was charged by the United States last week with 18 new counts related to conspiring to obtain and disclose classified information, endangering national security. He has been accused of unlawfully publishing the names of classified sources, and conspiring and with ex-Army intelligence analyst Chelsea Manning to obtain the classified information. He faces decades in prison if convicted.

"I am seriously, gravely concerned that if this man were to be extradited to the United States, he would be exposed to a politicized show trial and grave violations of his human rights," said Melzer, adding "The main narrative in this affair really is the United States wanting to make an example of Mr. Assange in order to deter other people from following his example."

Melzer also said that he didn't expect Assange to be tortured using traditional methods.

"I would much more expect him to be subjected to prolonged solitary confinement, to very harsh detention conditions and to a psychological environment which would break him eventually."