WikiLeaks founder Julian Assange was arrested in London Thursday, British police said, ending the long tenure of the anti-secrecy activist in Ecuador's embassy.

He had been holed up at the embassy in London since 2012, after Ecuador granted him asylum to avoid extradition to Sweden for sexual misconduct allegations.

His attorney, Jen Robinson, said Assange "has been arrested not just for breach of bail conditions but also in relation to a U.S. extradition request."

The U.K. Metropolitan Police Service said Assange was arrested on a warrant from 2012 for failing to surrender to the court.

One case against Assange has since expired but he had stayed in the country's London embassy over fears of being extradited and prosecuted in the U.S.

British authorities — respecting the international customs associated with the privileges each nation affords to another's diplomatic facilities — had patrolled the street outside Assange's window but not ventured inside to arrest him.

Last week, people gathered outside Ecuador's embassy in London, after WikiLeaks announced that Assange may be "expelled" from the building within "hours to days."

On the day of his arrest, WikiLeaks pleaded for his protection, tweeting, "Powerful actors, including CIA, are engaged in a sophisticated effort to dehumanise, delegitimize and imprison him."

The snowy-haired former Australian is facing criminal charges filed by the U.S. Department of Justice over the publication of classified government documents.

WikiLeaks gained notoriety in 2010 when it began to release troves of U.S. government secrets about the wars in Iraq and Afghanistan and the conduct of diplomacy around the world. The files also revealed the identities of people who had worked in Iraq and Afghanistan, prompting officials to say their lives had been put in danger.

Authorities in the United States have also suggested in court documents that Assange may have played an important role in the attack on the 2016 presidential election.

In January 2019 the Justice Department announced charges against GOP political consultant Roger Stone connected with what authorities called his work as an alleged intermediary between WikiLeaks and Donald Trump's 2016 presidential campaign.

Assange and WikiLeaks released an avalanche of stolen material in 2016 which embarrassed political targets, including the chairwoman of the Democratic National Committee and the chairman of Hillary Clinton's presidential campaign.

Prosecutors say Assange got the emails and other data from Russian military intelligence officers, part of the Kremlin's concerted wave of disruption aimed across the West.

WikiLeaks also revealed information about CIA surveillance tools in a separate release in 2017.

Assange asserted in early 2017 that Russia was not the source of the emails WikiLeaks released, an assertion The Washington Post's Fact Checker gave "three Pinocchios" at the time.

He has denied the accusations against him and insisted that he is a journalist protected by the First Amendment and other free-press laws across the West.

James Doubek contributed to this report.

This is a breaking news story and will be updated.

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