FORT MEADE, Maryland (AFP) - The computer hacker who turned in Bradley Manning said on Tuesday the tormented US soldier had never talked about helping Al-Qaeda after he leaked hundreds of thousands of classified documents.

On the second day of Manning's court martial, witness Adrian Lamo agreed with a defence attorney's portrait of the young soldier as a tortured soul who acted out of a desire to inform the public rather than to aid US enemies.

Under cross-examination from defence lawyer David Coombs, Mr Lamo said that a highly emotional Manning was also in the grip of a sexual identity crisis, which made him fear for the young soldier's life.

Military prosecutors allege that Manning - who admitted to leaking a vast cache of classified information to anti-secrecy website WikiLeaks between 2009 and 2010 - directly and knowingly aided Al-Qaeda through his actions.

However Mr Lamo said under questioning on Tuesday that the subject of helping America's enemies had never arisen during his contacts with Manning.

Mr Lamo engaged in online chats with Manning for six days between May 20 and May 26, 2010, shortly before the soldier was arrested.

Mr Lamo, who answered many questions simply with a "Yes" or a "No", told the hearing he had contacted police over his exchanges with Manning because he feared for the soldier's life.

Asked if Manning had ever uttered "a word against the United States" or whether "he wanted to help the enemy", Mr Lamo replied: "Not in those words, no."

He agreed with defence suggestions that Manning had been acting out of a sense of civic duty when he decided to leak the cache of secret files, and that Manning had been struggling with gender identity issues.

"He told you about his life, that he was struggling because of his gender identity issue? ... He told you he made a huge mess?' ... He was emotionally fractured?" Mr Coombs asked Mr Lamo.

"He needed moral and emotional support? ... He wondered if he didn't get it he might end up killing himself? (That he was) feeling desperate?... A broken soul?... Honestly scared?"

Mr Lamo - who was convicted in 2004 of unauthorised access to computers - said he suspected Manning contacted him because he was a known computer hacker and a supporter of the Lesbian Gay Bisexual and Transgender Defense League.

Mr Lamo also confirmed Mr Coombs statements that Manning had leaked the hundreds of thousands of incident reports from the wars in Iraq and Afghanistan and secret diplomatic cables out of a sincere desire to inform the public.

The US government has portrayed the leaks as an act of betrayal that put lives at risk, while Manning's supporters present him as a whistle-blower who gave the public a rare glimpse at the front lines of US wars and inside the halls of powers where US foreign policy is made and carried out.

Mr Lamo also indicated that Manning had no interest in trying to sell information to countries such as Russia or China, but instead believed the information belonged in the public domain.

Mr Lamo said Manning had admitted having contacts with WikiLeaks founder Julian Assange, who condemned the court martial on Tuesday as a "show trial."

Assange - who is holed up in the Ecuadoran embassy in London to avoid extradition to Sweden for questioning on sexual assault allegations - described the hearing as "a show of wasteful vengeance; a theatrical warning to people of conscience."

"This is not justice; never could this be justice. The verdict was ordained long ago," he wrote on the WikiLeaks site.

Rights activists meanwhile said the case hinged on the prosecution claim that Manning "aided" the enemy by releasing information to WikiLeaks.

"This trial is not about whether Manning leaked the documents to WikiLeaks; he's already admitted that he did," said Ben Wizner, of the American Civil Liberties Union.

"What's really being tested is the government's dangerous theory that leaking information to the press is equivalent to delivering it to the 'enemy.'"

Manning's trial at a military base outside Washington, DC is expected to last 12 weeks. Some evidence will be given behind closed doors for national security reasons.