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U.S. prosecutors are preparing to pursue a criminal case against Wikileaks founder Julian Assange, escalating a long battle targeting his anti-secrecy group.
According to a Thursday filing in an unrelated criminal case in a Virginia federal court, prosecutors have obtained a sealed indictment against Assange.
The charges were not immediately clear. Thursday's filing had been sealed, but was made public this week for reasons that were also unclear, according to a person familiar with the matter.
Joshua Stueve, a spokesman for the U.S. attorney's office in Alexandria, Virginia, said the filing was made an error. Wikileaks said it a Twitter post that it was an "apparent cut-and-paste error." Assange could not be reached for comment.
Lawyers for Assange and others have said his work with Wikileaks was critical to a free press and was protected speech.
"The notion that federal criminal charges could be brought based on the publication of truthful information is an incredibly dangerous precedent to set,” Barry Pollack, a U.S. lawyer for Assange, said in a statement.
The disclosure came as U.S. Special Counsel Robert Mueller investigates possible Russian interference in the 2016 U.S. presidential election, and possible collusion by U.S. President Donald Trump's White House campaign.
U.S. intelligence agencies have concluded that Russia obtained material through hacking, and Mueller's office has brought various criminal charges against Russians and Trump associates.
For its part, Wikileaks has faced scrutiny for publishing emails hacked before the election from the Democratic Party and the campaign chairman for Hillary Clinton, who Trump defeated.
Trump and Moscow have denied any interference or collusion. Assange has lived since 2012 in Ecuador's embassy in London, since receiving political asylum from the South American country, to avoid possible extradition to Sweden in a separate sexual molestation case.
Criminal charges in the United States would add pressure on Britain to extradite Assange, an Australian national.
U.S. officials have acknowledged that federal prosecutors in Virginia have been conducting a lengthy criminal probe into Assange and Wikileaks.
Thursday's filing related to a criminal case involving a 29-year-old man charged with enticing a 15-year-old girl.
The judge wrote in a detention memo that the defendant, Seitu Sulayman Kokayi, "has had a substantial interest in terrorist acts."
Reuters was unable to locate Kokayi. According to the filing, prosecutors sought to keep the charges confidential until after Assange's arrest, to ensure he did not evade or avoid arrest and extradition.
Any procedure "short of sealing will not adequately protect the needs of law enforcement at this time because, due to the sophistication of the defendant, and the publicity surrounding the case, no other procedure is likely to keep confidential the fact that Assange has been charged," the filing said.
Greg Barns, an Australian lawyer advising Assange, said in a statement it was "no surprise" that the United States was seeking to charge Assange, and Australian officials should allow Assange to return there.
Assange was initially welcomed at Ecuador's embassy, but Ecuador said last month it would no longer intervene with Britain on his behalf.
In a statement on Friday, Wikileaks said Assange was willing to work with British officials as long he was not extradited to the United States.
Ecuadorean officials had no immediate comment on Friday. Wikileaks gained prominence in 2010 after publishing a classified video showing a 2007 U.S. helicopter attack in Iraq that killed a dozen people, including two Reuters news staff.
It has also released thousands of classified U.S. military documents, among other disclosures.
U.S. Secretary of State Mike Pompeo has called Wikileaks a "hostile intelligence service," making that comment in April 2017 when he ran the U.S. Central Intelligence Agency.
Trump praised Wikileaks during his 2016 campaign.
