WikiLeaks founder Julian Assange has suffered “psychological torture” from a defamation campaign against him by the media, judges and senior political figures, a United Nations human rights investigator said on Friday.

Axar.az reports citing Reuters.

Nils Melzer, the U.N. special rapporteur on torture who visited Assange in a high-security London prison on May 9, voiced concern at fresh U.S. criminal charges laid against Assange and reiterated a call for him not to be extradited.

Assange was too ill on Thursday to appear via video link from a British prison in a hearing on an extradition request from the United States, his lawyer Gareth Peirce told Reuters. He is in a 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,” Melzer said in a statement.

The Swiss law professor, an independent expert, was accompanied on the prison visit by two medical experts specialized in examining potential victims of torture and other ill-treatment, the statement said. They spoke with Assange in private and conducted a “thorough medical assessment”.

“It was obvious that Mr. Assange’s health has been seriously affected by the extremely hostile and arbitrary environment he has been exposed to for many years,” Melzer said.

“In addition to physical ailments, Mr. Assange showed all symptoms typical for prolonged exposure to psychological torture, including extreme stress, chronic anxiety and intense psychological trauma.”

The United States is seeking the extradition of Assange, who was dragged from the Ecuadorean embassy in London on April 11 after his seven-year asylum was revoked, for one of the biggest ever leaks of classified information.

The Australian, now 47, had skipped bail and taken refuge there in 2012 to avoid extradition to Sweden over a sexual assault investigation that was later dropped. Sweden reopened the investigation in early May. Assange denies the rape allegation.