Julian Assange, founder of the whistleblower site WikiLeaks, has hailed a "significant victory" after a UN panel found that he is "arbitrarily detained".
Assange, who has been hiding in Ecuador's embassy in London since 2012 to avoid extradition to Sweden to face rape allegations, said on Friday that it was "now the task of the states of Sweden and the United Kingdom as a whole to implement the verdict" by letting him walk free from the embassy.
"We have today a really significant victory that has brought a smile to my face," Assange said, addressing a press conference via a video link from the embassy
Both Britain and Sweden denied that Assange was being deprived of freedom, noting he had entered the embassy voluntarily. They also dismissed the non-binding legal opinion of the UN panel.
Sweden's foreign ministry said that the panel had no right to "interfere in an ongoing case handled by a Swedish public authority".
Philip Hammond, UK foreign secretary, called Assange "a fugitive from justice", saying: "This is frankly a ridiculous finding by the working group and we reject it."
Melinda Taylor, a lawyer representing Assange, told Al Jazeera from London that she and her client were "obviously very disappointed" by the response of Hammond.
"We find it extremely surprising that the United Kingdom would say international law is ridiculous or that the United Nations charter is ridiculous and if they would disregard the obligations under binding convention such as the international covenant or the convention against torture in this case," she said.
The UN Working Group does not have the authority to order the release of a detainee - and Friday's ruling in unlikely to change the legal issues facing Assange - but it has considered many high-profile cases and its backing carries a moral weight that puts pressure on governments.
Al Jazeera's Barnaby Phillips, reporting from London, said: "Perhaps one positive outcome that may come from today's events is that the British, Ecuadorian and Swedish governments behind the scenes will feel a renewed pressure to come to some kind of a discreet diplomatic solution."
Assange walked into the embassy in June 2012 to avoid the threat of arrest and extradition to Sweden. He has lived there ever since in a small office room with a bed, computer, sun lamp, treadmill and access to a small balcony.
In a statement, the panel said it had adopted an opinion "in which it considered that Mr Julian Assange was arbitrarily detained by the governments of Sweden and the United Kingdom of Great Britain and Northern Ireland".
It added: "The working group also considered that the detention should be brought to an end and that Mr Assange should be afforded the right to compensation."
Swedish authorities want to speak to Assange about a rape allegation whose statute of limitations does not expire until 2020.
Elizabeth Fritz, the lawyer for the woman who has accused Assange of rape, said the UN ruling was offensive to her client.
"That a man who is wanted on an arrest warrant for rape should be awarded compensation for intentionally hiding from the judicial system for more than five years is offensive to my client and to the human rights of all victims of crime," she said.
Assange fears that if he went to Sweden, he could then be sent to the US and face prison.
Wikileaks' activities - including the release of 500,000 secret military files on the wars in Afghanistan and Iraq and 250,000 diplomatic cables - have infuriated the US.
The main source of the leaks, US Army soldier Chelsea Manning, was sentenced to 35 years in prison for breaches of the Espionage Act.