The US military has pressed criminal charges against a soldier suspected of leaking video of a US helicopter attack in Iraq to the website, WikiLeaks.
Army Spc Bradley Manning is accused of transferring classified data on to his personal computer and transmitting it to an unauthorised third party.
Spc Manning allegedly handed over footage of an Apache helicopter killing 12 civilians in Baghdad in 2007.
He was detained in Baghdad in June, two months after the video's publication.
The army has yet to say what leaked information led to the charges, however the date of the operation cited in the charge sheet matches that of the helicopter incident - 12 July 2007.
According to a US Army statement, Spc Manning was charged on Monday with eight violations of US criminal law and four violations of army regulations governing the handling of classified information and computers.
He is accused of downloading a classified video of a military operation in Iraq and transmitting it to an uncleared third party, in violation of a section of the Espionage Act, according to the charge sheet.
Spc Manning is also alleged to have abused access to a secret-level network to obtain more than 150,000 US state department cables, some of them classified. More than 50 cables are said to have been passed to an unauthorised person.
If convicted of all charges, he could face a prison sentence of between 50 to 70 years, according to army spokesman Lt Col Eric Bloom.
Col Bloom told the BBC that the next step would be an Article 32 hearing, at which time an investigating officer will determine whether the case should go to court-martial.
In the meantime, Spc Manning was free to retain his own counsel and make telephone calls, he added. It has yet to be decided if any court-martial would be open to the public.
Spc Manning is said to have confessed to leaking the video of the helicopter attack to WikiLeaks in a series of online chats with a former computer hacker, Adrian Lamo.
He allegedly also admitted handing over other items to WikiLeaks, including a classified army document assessing the threat level of the website, which promotes the leaking of information by whistleblowers.
WikiLeaks says it does not know whether Spc Manning was the source of the leak as it does not keep personal records of the people who approach it. It also denies it has any diplomatic cables.
However, the charge sheet accuses Spc Manning of obtaining a classified cable titled "Reykjavik 13", which was published by WikiLeaks on 18 February. The cable from the US embassy in Iceland describes meetings between its charge d'affaires Sam Watson, members of the Icelandic government and the British ambassador.
Following the army's announcement that Spc Manning had been charged, WikiLeaks posted a message on Twitter.
"If the charges against Manning are true, he will be the Daniel Ellsberg of our times," it said, referring to the US military strategist who leaked 7,000 pages of top-secret documents in an effort to halt the Vietnam War.
Mr Lamo meanwhile told the BBC that he would like to apologise to the 22-year-old.
"Not for doing what I did - which I believe was right - in that it protected US and coalition service men and women abroad," he said. "But what I am sorry for is that I was not a good friend to him."
"I put the interest of many ahead of the interest of one."
The video published by WikiLeaks in April shows an Apache helicopter opening fire on a group of about eight people, whom the pilots identify as armed insurgents.
After a voice on the transmission urges the pilots to "light 'em all up", the individuals on the street are shot by the gunship's cannon.
A few minutes later a van drives to the scene, and its occupants appear to start picking up a wounded person. It, too, is fired upon.
Two children were among the casualties, along with a photographer working for the Reuters news agency and his assistant.
The US military initially said the helicopters had been engaged in combat operations against a hostile force.