Julian Assange has urged the US to end its “witch-hunt” against WikiLeaks, in his first public statement since entering Ecuador’s London embassy.
Julian Assange also called for the release of Bradley Manning, who is awaiting trial in the US accused of leaking classified documents to the Wikileaks site.
He spoke from a balcony at the embassy and thanked Ecuador’s president, who has granted him asylum.
Julian Assange faces extradition to Sweden over sexual assault claims, which he denies.
He said: “As WikiLeaks stands under threat, so does the freedom of expression and the health of all our societies.
“We must use this moment to articulate the choice that is before the government of the United States of America.
“Will it return to and re-affirm the revolutionary values it was founded on?
“Or will it lurch off the precipice, dragging us all into a dangerous and oppressive world in which journalists fall silent under the fear of prosecution and citizens must whisper in the dark?”
The US is carrying out an investigation into WikiLeaks, which has published a mass of leaked diplomatic cables, embarrassing several governments and international businesses.
Alleged WikiLeaks source Bradley Manning, 24, an intelligence analyst in the American army who served in Iraq, is alleged to have leaked US government cables to the whistle-blowing website. He is set to face a court martial.
In an interview for US television in 2010, Julian Assange denied any knowledge of Pte Manning.
Julian Assange began his speech by thanking his supporters, many of whom have been holding a vigil outside the building in Knightsbridge.
Speaking of the visit by police officers to the embassy on Wednesday, Julian Assange said: “Inside this embassy after dark, I could hear teams of police swarming up into the building through its internal fire escape. But I knew there would be witnesses and that is because of you.
“If the UK did not throw away the Vienna Conventions the other night it is because the world was watching and the world was watching because you were watching.”
It is an established international convention that local police and security forces are not permitted to enter an embassy, unless they have the express permission of the ambassador.
The Foreign Office has said it remained committed to reaching a “negotiated solution” but following its obligations under the Extradition Act, it would arrest Julian Assange if he left the embassy.
In 2010, two female ex-WikiLeaks volunteers accused Julian Assange, an Australian citizen, of committing sexual offences against them while he was in Stockholm to give a lecture.
Julian Assange claims the sex was consensual and the allegations are politically motivated.
In a statement issued after the Ecuadorean decision to grant Julian Assange political asylum, Foreign Secretary William Hague said the UK was under a “binding obligation” to extradite him to Sweden.