A military judge has acquitted former US intelligence analyst Bradley Manning of the most serious charge against him, aiding the enemy, but convicted him of espionage, theft and computer fraud charges for giving thousands of classified secrets to the anti-secrecy site WikiLeaks.

He faces a maximum sentence up to 136 years.

The judge on Tuesday deliberated for about 16 hours over three days before reaching her decision in a case that drew worldwide attention. Supporters hailed Manning as a whistleblower. The US government called him an anarchist computer hacker and attention-seeking traitor.

The WikiLeaks case is by far the most voluminous release of classified material in US history. Manning's supporters included Pentagon Papers leaker Daniel Ellsberg, who in the early 1970s spilled a secret Defence Department history of US involvement in Vietnam that showed that the US government repeatedly misled the public about the war.

Manning's sentencing begins on Wednesday. The charge of aiding the enemy was the most serious of 21 counts and carried a potential life sentence.

His trial was unusual because he acknowledged giving WikiLeaks more than 700,000 battlefield reports and diplomatic cables, plus video of a 2007 US helicopter attack that killed civilians in Iraq and a Reuters news

photographer and his driver. In the footage, airmen laughed and called targets "dead bastards".

'Good-intentioned'

Manning pleaded guilty earlier this year to lesser offences that could have brought him 20 years behind bars, yet the government continued to pursue the original, more serious charges.

Manning has said he leaked the material to expose the U.S military's "bloodlust" and disregard for human life, and what he considered American diplomatic deceit. He said he chose information he believed would not the harm the US, and he wanted to start a debate on military and foreign policy. He did not testify at his trial.

Bradley Manning: Truth on trial?

Defence attorney David Coombs portrayed Manning as a "young, naive but good-intentioned" soldier who was in emotional turmoil, partly because he was a gay service member at a time when homosexuals were barred from serving openly in the US military.

Coombs said Manning could have sold the information or given it directly to the enemy, but he gave them to WikiLeaks in an attempt to "spark reform" and provoke debate. A counterintelligence witness valued the Iraq and Afghanistan war logs at about $5.7m, based on what foreign intelligence services had paid in the past for similar information.

Coombs said Manning had no way of knowing whether al-Qaeda would access the secret-spilling website, and a 2008 counterintelligence report showed the government itself didn not know much about the site.

Not so naive?

JD Gordon, former Defence Department spokesperson, told Al Jazeera that the Obama administration has made an example of Manning.

“I think that he [Bradley Manning] was a spy and a traitor. He was involved in this 21st century type of warfare. He is more like a criminal instead of a whistle-blower. So I am pleased with the judge’s decision today,” he said.

The lead prosecutor, Major Ashden Fein, said Manning knew the material would be seen by al-Qaeda, a key point prosecutor needed to prove to get an aiding the enemy conviction. Even Osama bin Laden had some of the digital files at his compound in Pakistan when he was killed.

The Manning trial unfolded as another low-level intelligence worker, Edward Snowden, revealed US secrets about surveillance programs. Snowden, a civilian employee, has told The Guardian newspaper his motives were similar to Manning's, but he said his leaks were more selective.

Manning's supporters believed a conviction for aiding the enemy would have a chilling effect on leakers who want to expose wrongdoing by giving information to websites and the media.