FORT MEADE (AP) — Bradley Manning a private in the US army was sentenced Wednesday to 35 years in prison for giving hundreds of thousands of secret military and diplomatic documents to WikiLeaks in one of the nation’s biggest leak cases since the Pentagon Papers more than a generation ago.

In a brief hearing, military judge Colonel Denise Lind didn’t offer any explanation for the sentence she gave Manning. The former intelligence analyst was found guilty last month of 20 crimes, including six violations of the Espionage Act, as part of the Obama administration’s unprecedented crackdown on media leaks.

But the judge acquitted him of the most serious charge, aiding the enemy, an offense that could have meant life in prison without parole.

Manning could have received 90 years behind bars. Prosecutors asked for at least 60 years as a warning to other soldiers, while Manning’s lawyer suggested he get no more than 25, because some of the documents he leaked will be declassified by then.

The native of Crescent, Oklahoma, digitally copied and released more than 700,000 documents, including Iraq and Afghanistan battlefield reports and State Department cables, while working in 2010 in Iraq.

He also leaked video of a 2007 Apache helicopter attack in Baghdad that mistakenly killed at least nine people, including a Reuters photographer.

A potentially more explosive leak case unfolded as Manning’s court-martial was underway, when former National Security Agency contractor Edward Snowden was charged with espionage for exposing the NSA’s Internet and telephone surveillance programmes.

At his trial, Manning said he gave the material to the secrets-spilling website WikiLeaks to expose the US military’s “bloodlust” and generate debate over the wars and US policy.

During the sentencing phase, he apologised for the damage he caused, saying, “When I made these decisions, I believed I was going to help people, not hurt people.”

His lawyers also argued that Manning suffered extreme inner turmoil over his gender identity — his feeling that he was a woman trapped in a man’s body — while serving in the macho military, which at the time barred gays from serving openly. Among the evidence was a photo of him in a blond wig and lipstick.

Defence attorney David Coombs told the judge that Manning had been full of youthful idealism.

“He had pure intentions at the time that he committed his offenses,” Coombs said. “At that time, Pfc Manning really, truly, genuinely believed that this information could make a difference.”

Prosecutors did not present any evidence in open court that anyone was physically harmed as a direct result of Manning’s actions. But they showed that al-Qaida used material from the helicopter attack in a propaganda video and that Osama bin Laden presumably read some of the leaked documents, which were published online by WikiLeaks. Some of the material was found in bin Laden’s compound when it was raided.

Also, government witnesses testified the leaks endangered US intelligence sources, some of whom were moved to other countries for their safety. And several ambassadors were recalled, expelled or reassigned because of embarrassing disclosures.

Prosecutors called Manning an anarchist and an attention-seeking traitor, while supporters have hailed him as a whistleblower and likened him to Daniel Ellsberg, the defence analyst who in 1971 leaked the Pentagon Papers, a secret history of US involvement in Vietnam, to The New York Times and other newspapers.

That case touched off an epic clash between the Nixon administration and the press and led to a landmark Supreme Court ruling on the First Amendment.

The Obama administration has charged seven people with leaking to the news media, while only three people were prosecuted in all previous administrations combined.

Among those seven is Snowden, whose leak has triggered a fierce debate over security vs. privacy and strained US relations with Russia, which is harbouring him despite demands he be returned to this country to face charges.