Julian Assange has been hit with an 18-count indictment that supersedes the charge announced in April when the WikiLeaks founder was dragged out of the Ecuadorian embassy in London.
The United States is alleging that Assange conspired with, and "aided and abetted", Chelsea Manning to remove US classified documents. It also alleges that Assange published on WikiLeaks the unredacted names of sources in Iraq and Afghanistan that provided information to the US.
"These human sources included local Afghans and Iraqis, journalists, religious leaders, human rights advocates, and political dissidents from repressive regimes," a statement from the US Department of Justice (DOJ) said.
"According to the superseding indictment, Assange's actions risked serious harm to United States national security to the benefit of our adversaries and put the unredacted named human sources at a grave and imminent risk of serious physical harm and/or arbitrary detention."
In a briefing, US officials said they were not charging Assange for acting as a publisher, but rather because he endangered the lives of sources.
"Assange is charged for his alleged complicity in illegal acts to obtain or receive voluminous databases of classified information and for agreeing and attempting to obtain classified information through computer hacking," US Attorney G. Zachary Terwilliger said.
"The United States has not charged Assange for passively obtaining or receiving classified information.
"Instead, the United States has only charged Assange for publishing a narrow set of classified documents in which Assange also allegedly published the unredacted names of innocent people who risked their safety and freedom to provide information to the United States and its allies."
The unsealed indictment details allegations of Assange seeking classified information, and Manning running searches on classified systems for such information and allegedly downloading four databases containing 90,000 Afghanistan war activity reports, 400,000 reports on the Iraq war, 800 Guantanamo Bay detainee assessment briefs, and 250,000 cables from the US Department of State.
The new indictment also contains the password hash cracking allegations unsealed last month, and revealed that copies of the WikiLeaks-published documents were allegedly found in the compound of Osama Bin Laden.
Assange is facing up to a maximum of 10 years imprisonment on each count if found guilty, except for the count relating to conspiracy to commit computer intrusion, which carries five years.
"Actual sentences for federal crimes are typically less than the maximum penalties," the DOJ said.
In response to the unsealing of the indictment, the American Civil Liberties Union said the charges were "a direct assault on the First Amendment".
"These charges are an extraordinary escalation of the Trump administration's attacks on journalism, establishing a dangerous precedent that can be used to target all news organizations that hold the government accountable by publishing its secrets," it said.
"The charges against Assange are equally dangerous for US journalists who uncover the secrets of other nations. If the US can prosecute a foreign publisher for violating our secrecy laws, there's nothing preventing China, or Russia, from doing the same."
Assange is currently serving 50 weeks in jail in the United Kingdom for skipping bail.
Last week, Manning was jailed again for refusing to testify to the grand jury investigating WikiLeaks. Manning had been briefly released from jail when the former grand jury's terms expired, before she was sent back under a second subpoena.
WikiLeaks called the charges the "evil of lawlessness" and a "blatant extraterritorial assault" in a statement.
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