After visiting Julian Assange at Belmarsh Prison in London, a United Nations rapporteur said the Wikileaks founder was displaying "extreme stress, chronic anxiety and intense psychological trauma” after years of being subjected to "progressively severe forms of cruel, inhuman or degrading treatment.”

Nils Melzer, the U.N.’s special rapporteur on torture and other cruel, inhumane or degrading treatment or punishment, was accompanied by two medical experts during the visit on May 9. Assange has served seven weeks of a 50-week sentence for violating bail conditions and avoiding extradition to Sweden on charges in 2012 of sexual misconduct and rape. After denying the charges, he sought asylum in 2012 at Ecuador’s London embassy and remained there until the South American nation allowed his removal by police in April.

Assange also faces possible extradition to the U.S. which has charged the Australian national with 17 counts under the Espionage Act of 1917 for attempting to hack government computers in association with former U.S. Army intelligence analyst Chelsea Manning. Critics argue the U.S. charges have free speech implications. If extradited to the U.S. and convicted of all espionage charges, Assange faces up to 175 years in prison.

Melzer said Assange had 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.”

Sweden dismissed the sexual misconduct charges against Assange in 2015 after the expiration of statutory limits, and the rape count in 2017, citing his exile as an insurmountable obstacle to prosecution. However, the case was reopened upon his expulsion from the Ecuadorian embassy, setting up a grim gauntlet of competing legal proceedings against him on multiple continents.

Melzer has appealed to the British government, asking it not to extradite Assange to the U.S. “or any other state failing to provide reliable guarantees against his onward transfer to the United States.” Melzer added he had an “urgent concern” Assange could be exposed to serious violations of human rights, including his freedom of expression and right to a fair trial, and may face torture or other cruel, inhuman or degrading treatment, if extradited.

"In 20 years of work with victims of war, violence and political persecution I have never seen a group of democratic States ganging up to deliberately isolate, demonize and abuse a single individual for such a long time and with so little regard for human dignity and the rule of law,” he said in a statement.

Melzer added there had been a "relentless and unrestrained campaign of public mobbing, intimidation, and defamation against Mr. Assange, not only in the United States, but also in the United Kingdom, Sweden and, more recently, Ecuador."

In a statement Friday, Wikileaks reported Assange was in such poor health it was impossible to have a normal conversation with him.

"Since 2010, when Wikileaks started publishing evidence of war crimes and torture committed by U.S. forces, we have seen a sustained and concerted effort by several States towards getting Mr. Assange extradited to the United States for prosecution, raising serious concern over the criminalization of investigative journalism in violation of both the U.S. Constitution and international human rights law," Melzer said.