Washington (CNN) WikiLeaks founder Julian Assange has been charged with helping the former Army intelligence specialist Chelsea Manning access Defense Department computers in 2010 in an effort to disclose secret government documents, the US Justice Department announced Thursday morning, hours after Assange was forcibly removed by authorities from the Ecuadoran embassy in London .

More than a year ago, a federal grand jury indicted Assange for one count of conspiracy to commit computer intrusion.

The case had been kept under seal until Thursday, and its unveiling marks a new chapter in the US government's high-profile efforts to discourage classified document leaks and to pursue Assange.

It's not clear yet whether or how Assange's claims as a journalist under the First Amendment, which his organization, supporters and lawyers have pushed, will factor into this case. He and WikiLeaks also play a role in separate allegations that Russian military intelligence hackers illegally accessed Democratic Party servers during the 2016 election, but special counsel Robert Mueller did not charge Assange or WikiLeaks with any related crimes.

The Justice Department Thursday said Assange's charge Thursday relates to "one of the largest compromises of classified information in the history of the United States."

Assange will be brought to the Eastern District of Virginia federal court once in the US, according to the indictment. Authorities and his lawyer said the US is seeking to extradite him.

He has not entered a plea in US court

Barry Pollack, an attorney for Assange, says the allegations against Assange in the indictment made public "boil down to encouraging a source to provide him information and taking efforts to protect the identify of that source. Journalists around the world should be deeply troubled by these unprecedented criminal charges."

Assange was found guilty Thursday in London of breaking his bail conditions and ordered to appear on May 2 for an extradition hearing. Until then, he will remain in custody.

The charge announced Thursday is against Assange, though Manning is a named conspirator in the case. Manning has been held in jail in recent weeks for refusing to testify against Assange before a grand jury this year.

Allegations detailed

Assange's alleged crime dates to 2010, when he agreed to help Manning, then a US Army intelligence analyst, "in cracking a password" on Defense Department computers to access a secure network of US government classified documents, according to the indictment.

This allowed Manning to use a different username than her own to log onto the government network. Manning and Assange discussed their ploy in real time, prosecutors said.

Assange had encouraged Manning to get the records, the indictment alleges, and both took steps to obscure Manning's identity as Wikileaks' leaker.

At one point, in March 2010, Assange asked Manning about information on the password, and said he had "no luck so far" in cracking it, the indictment said.

"At the time he entered this agreement, Assange knew that Manning was providing WikiLeaks with classified records containing national defense information of the United States," the indictment says. "Assange was knowingly receiving such classified records from Manning for the purpose of publicly disclosing them on the WikiLeaks website."

Assange and Manning spoke to one another over the chat service "Jabber," the indictment says.

If found guilty, the charge Assange faces carried a maximum penalty of five years in prison.

More charges expected in future

Justice Department officials expect to bring additional charges Assange, a US official briefed on the matter said. It is unclear when such charges would be brought.

The years-long FBI investigation into Assange transformed in recent years with the recovery of communications that prosecutors believe show Assange had been been a more active participant in a conspiracy to hack computers and violating US law, law enforcement officials say.

The Justice Department had struggled for years with the question of whether Assange and WikiLeaks should be treated as journalists and publishers. News organizations similarly published stolen classified documents, some even worked with WikiLeaks to get access to documents and publish stories.

The view among prosecutors began changing late in the Obama administration, in part due to new evidence the FBI believed showed Assange was not entitled to journalistic protections.

In 2017, the WikiLeaks publication of stolen CIA hacking codes helped propel the case against Assange, according to current and former US law enforcement officials.

The FBI also weighed the organization's role in the 2016 publication of documents hacked by Russian intelligence agencies. But investigators for months struggled to connect Assange directly to the hacks of the Democratic National Committee and Hillary Clinton campaign officials. Investigators had access to monitoring of multiple communications methods that Assange used during that period. It's not clear whether that eavesdropping eventually turned up evidence that can be used in a case against Assange.

Signs of indictment

Signs that the US was moving on the case emerged in recent weeks when prosecutors subpoenaed Manning to testify before a grand jury in Alexandria, Virginia. She remains detained because she has refused to testify before a grand jury about her disclosure of military and diplomatic secrets to WikiLeaks.

On Thursday, Moira Meltzer-Cohen, an attorney for Manning, said Assange's arrest does not offer a "foregone conclusion" that her client will be released.

"Were (Assange) to be extradited we hope it would signal her release but that is not, unfortunately, a foregone conclusion," Meltzer-Cohen said.

Longtime pursuit

Manning previously faced charges related to the same leak that ensnared Assange on Thursday.

In Assange's case, prosecutors note how Manning downloaded four "nearly complete" databases from US agencies, largely regarding documents about the war in Afghanistan, briefs on Guantanamo Bay detainees and diplomatic cables, and Wikileaks published the documents online in 2010 and 2011.

The leaked files that underpin Assange's charge Thursday include the diplomatic cables and the pursuit of Guantanamo Bay detainee records, prosecutors said in the indictment.

Manning had told Assange in March 2010 she was "throwing everything [she had] on JTF GTMO at [Assange] now," according to Thursday's indictment. "After this upload, that's all I really have got left," Manning said.

"Curious eyes never run dry in my experience," Assange allegedly replied.

Manning was arrested in 2010 and later charged with leaking thousands of classified files. After an eight-week military trial in 2013, she was found guilty of several counts, including violations of the Espionage Act, and sentenced to 35 years in prison. That sentence was commuted by President Barack Obama in 2017.

Assange's arrest Thursday was precipitated by mounting tensions between Assange and his long-time Ecuadoran hosts, and executed through a treaty between the UK and US to extradite defendants.

The US Department of Homeland Security issued a "red notice" for Assange on the worldwide law enforcement network Interpol as early as March 2011, according to a diplomatic source with first-hand knowledge of the document.

The source said the red notice did not mention any charges in particular at the time.

A red notice is a request to law enforcement worldwide to locate and provisionally arrest a person pending extradition, surrender, or similar legal action, according to Interpol. It is not an arrest warrant.