WASHINGTON (AP) — The U.S. filed new charges Thursday against Wikileaks founder Julian Assange, accusing him of placing the United States at risk of "serious harm" by publishing thousands of secret and classified documents, including the names of confidential sources for American armed forces.

In an 18-count, superseding indictment, Justice Department prosecutors allege that Assange directed former Army intelligence analyst Chelsea Manning in one of the largest compromises of classified information in U.S. history.

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The case presents immediate questions about media freedom, including whether the Justice Department is charging Assange for actions — such as soliciting and publishing classified information — that ordinarily journalists do as a matter of course. Department officials said Thursday they believe Assange strayed far outside First Amendment protections.

The new Espionage Act charges go far beyond an initial indictment against Assange made public last month that accused him of conspiring with Manning to crack a defense computer password.

14 PHOTOS Julian Assange See Gallery Julian Assange WikiLeaks founder Julian Assange makes a speech from the balcony of the Ecuadorian Embassy, in central London, Britain February 5, 2016. REUTERS/Peter Nicholls/Files A supporter of Wikileaks founder Julian Assange holds a banner outside the Ecuadorian embassy in London as he marks three years since Assange claimed asylum in the embassy on June 19, 2015. WikiLeaks founder Julian Assange clocks up three years inside the Ecuadoran embassy in London today, after claiming that Swedish prosecutors cancelled a landmark meeting in his case earlier this week. AFP PHOTO / JUSTIN TALLIS (Photo credit should read JUSTIN TALLIS/AFP/Getty Images) A supporter of Wikileaks founder Julian Assange holds banners outside the Ecuadorian embassy in London as he marks three years since Assange claimed asylum in the embassy on June 19, 2015. WikiLeaks founder Julian Assange clocks up three years inside the Ecuadoran embassy in London today, after claiming that Swedish prosecutors cancelled a landmark meeting in his case earlier this week. AFP PHOTO / JUSTIN TALLIS (Photo credit should read JUSTIN TALLIS/AFP/Getty Images) Julian Assange, Founder and Editor-in-Chief of WikiLeaks speaks via video link during a press conference on the occasion of the ten year anniversary celebration of WikiLeaks in Berlin, Germany, October 4, 2016. REUTERS/Axel Schmidt TPX IMAGES OF THE DAY WikiLeaks founder Julian Assange appears on screen via video link during his participation as a guest panelist in an International Seminar on the 60th anniversary of the college of Journalists of Chile in Santiago, Chile, July 12, 2016. REUTERS/Rodrigo Garrido File photo dated 05/02/16 of WikiLeaks founder Julian Assange, who will publish more confidential documents on the US Central Intelligence Agency once a "key attack code" has been disarmed, he has revealed. File photo dated 5/2/2016 of Julian Assange who has defended the release of emails by WikiLeaks about US presidential candidate Hillary Clinton. WikiLeaks founder Julian Assange speaking from the balcony of the Ecuadorian Embassy in London where he has been living for more than three years after the country granted him political asylum. BERLIN, GERMANY - OCTOBER 4: WikiLeaks founder Julian Assange participates via video link at a news conference marking the 10th anniversary of the secrecy-spilling group in Berlin, Germany on October 4, 2016. (Photo by Maurizio Gambarini/Anadolu Agency/Getty Images) The Spanish journalist Ignacio Ramonet presents in Quito, Ecuador, on June 23, 2016 the Ecuador 's book " When Google found Wikileaks". Julian Assange made his appearance to the world in 2010 with the publication by WikiLeaks of thousands of secret documents revealing conspiracies , corruption, crimes , lies, and incriminate several governments and particularly the United States as the main actor illegalities. (Photo by Rafael Rodrï¿½uez/ACGPHOTO/NurPhoto via Getty Images) LONDON, ENGLAND - FEBRUARY 05: Wikileaks founder Julian Assange prepares to speak from the balcony of the Ecuadorian embassy where he continues to seek asylum following an extradition request from Sweden in 2012, on February 5, 2016 in London, England. The United Nations Working Group on Arbitrary Detention has insisted that Mr Assange's detention should be brought to an end. (Photo by Carl Court/Getty Images) LONDON, ENGLAND - FEBRUARY 05: A panel of WikiLeaks representitives and press look on as WikiLeaks founder Julian Assange speaks at a press conference at the Frontline Club via video link from the Ecuadorian Embassy in London on 5 February 2016 in London, England. Mr Assange's speech comes a day after it was announced that the UN panel ruled he was being unlawfully detained at the Ecuadorian Embassy. (Photo by Chris Ratcliffe/Getty Images) Australian founder of whistleblowing website, 'WikiLeaks', Julian Assange speaks to media after giving a press conference in London on July 26, 2010. The founder of a website which published tens of thousands of leaked military files about the war in Afghanistan said Monday they showed that the 'course of the war needs to change'. In all, some 92,000 documents dating back to 2004 were released by the whistleblowers' website Wikileaks to the New York Times, Britain's Guardian newspaper, and Germany's Der Spiegel news weekly. Assange also used a press conference in London to dismiss the White House's furious reaction to the disclosures. AFP PHOTO/Leon Neal (Photo credit should read LEON NEAL/AFP/Getty Images) MELBOURNE, AUSTRALIA - MAY 21: (AUSTRALIA OUT) Wikileaks founder Julian Assange poses during a portrait shoot on May 21, 2010 in Melbourne, Australia. (Photo by Mark Chew/Fairfax Media/Fairfax Media via Getty Images). Up Next See Gallery Discover More Like This HIDE CAPTION SHOW CAPTION of SEE ALL BACK TO SLIDE

Wikileaks caused particular harm by publishing the names of people who helped American forces in Iraq and Afghanistan and U.S. diplomats around the world.

The new indictment says Assange conspired with Manning to obtain and disclose classified national defense documents, including State Department cables and reports on the wars in Iraq and Afghanistan. Prosecutors say his actions "risked serious harm" to the United States.

Assange, 47, is in custody in London after being evicted from the Ecuadorian Embassy in April. The U.S. is seeking his extradition.

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