WikiLeaks says founder Julian Assange has boarded a plane and left the United Kingdom after negotiations with the US Department of Justice and a deal that "has not yet been formally finalised".
"Julian Assange is free," the publisher said in a statement on X.
"He left Belmarsh maximum security prison on the morning of 24 June, after having spent 1901 days there.
"He was granted bail by the High Court in London and was released at Stansted airport during the afternoon, where he boarded a plane and departed the UK."
A video posted by WikiLeaks shows Assange sitting in an unknown location with a piece of paper in his hand, shortly before boarding a plane.
Earlier, it was reported that Assange was expected to plead guilty this week to
, in a deal that could end his imprisonment in the UK and allow him to return home to Australia, US prosecutors said.
US prosecutors said in court papers that Assange, 52, has agreed to plead guilty to a single criminal count of conspiring to obtain and disclose classified US national defence documents, according to filings in the US District Court for the Northern Mariana Islands.
Assange is due to be sentenced at a hearing on the island of Saipan at 9am on Wednesday. He will likely be credited for the time he has already served and face no new jail time.
According to the Associated Press, the hearing would take place there because of Assange's opposition to travelling to the continental US, and the court's proximity to Australia.
The Australian government said that given legal proceedings in the US were ongoing, it was "not appropriate to provide further comment".
"The Australian government continues to provide consular assistance to Mr Assange," a spokesperson added in a statement to SBS News.
"Prime Minister (Anthony) Albanese has been clear — Mr Assange's case has dragged on for too long and there is nothing to be gained by his continued incarceration."
WikiLeaks in its statement added that a global campaign had led to negotiations with the US Department of Justice, "leading to a deal that has not yet been formally finalised".
"We will provide more information as soon as possible," it added.
"As he returns to Australia, we thank all who stood by us, fought for us, and remained utterly committed in the fight for his freedom."
A screenshot of a video posted by WikiLeaks of Julian Assange boarding a plane at where the publisher said was Stansted airport in London. Source: Supplied / WikiLeaks/X
In 2010, WikiLeaks released hundreds of thousands of classified US military documents on Washington's wars in Afghanistan and Iraq — the largest security breaches of their kind in US military history — along with swaths of diplomatic cables.
Assange was indicted during former US president Donald Trump's administration, over WikiLeaks' mass release of secret US documents, which were leaked by Chelsea Manning, a former US military intelligence analyst who was also prosecuted under the Espionage Act.
The trove of more than 700,000 documents included diplomatic cables and battlefield accounts such as a 2007 video of a US Apache helicopter firing at suspected insurgents in Iraq, killing a dozen people including two Reuters news staff. That video was released in 2010.
The charges against Assange sparked outrage among his many global supporters, who have long argued that Assange, as the publisher of Wikileaks, should not face charges typically used against federal government employees who steal or leak information.
Many press freedom advocates have argued that criminally charging Assange threatens free speech.
Assange was first arrested in Britain in 2010 on a European arrest warrant after Swedish authorities said they wanted to question him over sex-crime allegations that were later dropped. He fled to Ecuador's embassy, where he remained for seven years, to avoid extradition to Sweden.
He was dragged out of the embassy in 2019 and jailed for skipping bail. He has been in London's Belmarsh top security jail ever since, from where he has for almost five years been fighting extradition to the United States.
Those five years of confinement are similar to the sentence imposed on Reality Winner, an Air Force veteran and former intelligence contractor, who was sentenced to 63 months in prison after she removed classified materials and mailed them to a news outlet.
While in Belmarsh, Assange married his partner Stella with whom he had two children while he was taking refuge in the Ecuadorean embassy.
