WikiLeaks founder Julian Assange has been charged in the US, unsealed court documents there have inadvertently revealed.
The information was contained in a court filing in an unrelated case.
It is not clear what charges Mr Assange faces, because they were not disclosed.
However the US Mueller inquiry into alleged Russian election interference has suggested that WikiLeaks was used by Russian intelligence to distribute hacked material.
US intelligence agencies say Russia was aiming to harm the chances of Hillary Clinton and favour Donald Trump in the 2016 election by releasing hacked emails belonging to a Clinton aide. Russia denies this.
Mr Assange fled to Ecuador’s London embassy in 2012 to escape extradition to Sweden on since-dropped sexual assault charges and has stayed there over fears he could be extradited to the US if he leaves.
The court filing was from a prosecutor in the eastern Virginia state district court, Assistant US Attorney Kellen Dwyer.
The Justice Department said the filing was made in error, while WikiLeaks believed it was a “cut and paste” mistake.
The defendant in the case, Seitu Sulayman Kokayi, is charged with coercion and enticement of a minor.
In the filing, Mr Dwyer says documents should remain sealed 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 documents “would need to remain sealed until Assange is arrested in connection with the charges in the criminal complaint and can therefore no longer evade or avoid arrest and extradition in this matter,” Mr Dwyer goes on to say.
One of Mr Assange’s lawyers told the Guardian newspaper that charging someone for publishing accurate information was a “dangerous path for a democracy to take”.
“The news that criminal charges have apparently been filed against Mr Assange is even more troubling than the haphazard manner in which that information has been revealed,” Barry Pollack told the newspaper.
US media reports say US officials are increasingly confident that Mr Assange will be detained and face charges in the US.
Earlier this year the British government said it was holding talks with Ecuador over Mr Assange’s fate.
Ecuador’s President Lenin Moreno has said he was never “in favour” of Mr Assange’s activities and has described him as a “stone in our shoe”.