Julian Assange accuses the US administration of trying to erect a 'national regime of secrecy' and calls on the government to cease its investigation of WikiLeaks Reuters

The WikiLeaks founder, Julian Assange, has accused President Obama of seeking to exploit the Arab spring revolutions for political gain, claiming Obama's vocal support for freedom of expression had not been translated into action.

Assange was speaking to a gathering of diplomats at the UN general assembly through a satellite videolink from the Ecuadorean embassy in London, where he sought refuge three months ago from extradition to Sweden, where he is wanted for questioning on allegations of sex offences.

The meeting was hosted by the Ecuadorean foreign minister, Ricardo Patiño, who said he would once more demand the UK grant Assange safe passage to Ecuador when he meets his British counterpart, William Hague, later on Thursday. He accused the British government of violating Assange's human rights, saying he could be stuck in the embassy in London for 10 years, which would have a severe impact on his health.

Assange, dressed in a shirt and half-knotted tie, appeared tired and unwell on the video. He had dark rings under his eyes and sniffed frequently during a prepared presentation. Assange focused largely on Barack's Obama address to the UN on Tuesday in which the president gave a staunch defence of freedom of speech, and voiced American support for the revolutions in the Arab world.

Assange said that it was "audacious" for the US government "to take credit for the last two years of progress", given past American support for the ousted Arab dictators. He said Mohammed Bouazizi, a Tunisian street pedlar whose suicide from despair over his life in January last year sparked the revolt, "did not set himself on fire so that Barack Obama could get re-elected".

He added that it was "disrespect to the dead to claim that the United States supported the forces of change".

Instead, Assange claimed that it was the leak of classified US diplomatic cables to WikiLeaks, allegedly by a US soldier in military intelligence, Bradley Manning, that "went on to help trigger the Arab spring".

Referring to Obama's UN defence of the freedom of expression, Assange pointed to the treatment of Manning in US prison, where he was held in isolation, stripped and left naked for hours in his cell, and to the denunciation of WikiLeaks by American leaders.

"The time for words has run out. It is time to cease the persecution of our people and our alleged sources. It is time to join the force of change, not in fine words but in fine deeds," Assange said.

Assange and the Ecuadorean government argue that if he goes to Sweden to face the sexual assault allegations against him, he could be extradited from there to the US to face politically-motivated prosecution. The Sydney Morning Herald has published what it described as declassified US air force counter-intelligence reports which designated Assange and WikiLeaks as "enemies of the United States", the same legal category as al-Qaida and the Taliban.

The British government said it is legally obliged to carry out Assange's extradition after the Australian's appeals in the British courts were rejected. It has also said that according to European law, it would not allow extradition to the United States on charges that could result in the death penalty. Patiño argued that the UK's human rights obligations overrode its duty under EU treaty.

"The United Kingdom says it defends human rights," Patiño said. "Would it be human to try to keep Mr Assange in the embassy for months or years?" He added that Assange might spend up to 10 years in the embassy "without right to his life or his privacy".