Bradley Manning must face 'aiding the enemy' charge

Private Bradley Manning has not yet entered a plea

A US military judge has refused to dismiss the most serious charge against Private Bradley Manning, the alleged source of Wikileaks revelations.

The charge of aiding the enemy - one of 22 charges he faces - carries a life sentence in prison.

Col Denise Lind ruled against a defence argument that the government had not properly alleged that Pte Manning intended to help al-Qaeda.

Pte Manning's court martial is set to begin on 21 September in Maryland.

In arguing the case for keeping the charge in place, prosecutors said Pte Manning knew the information would be seen by al-Qaeda, regardless of whether that was his main intention.

Col Lind eventually ruled that the charge must be proven during the court martial.

If prosecutors fail to prove Pte Manning knew he was giving information to the enemy, Col Lind said she would consider further motions from the defence.

'Irrelevant' reports

While the court martial date has been set, Pte Manning has not yet entered a plea, or decided whether he will be tried by a judge or a jury.

During pre-trial hearings, Col Lind also heard arguments about whether or not the leaked material actually harmed US interests - and whether this mattered.

Defence lawyer David Coombs said he believed the reports would show the leaks did little harm. If Wikileaks had created significant harm to the US, the prosecution would be eager to discuss them, Mr Coombs said.

Prosecutor Maj Ashden Fein called the reports "completely irrelevant", arguing the government did not have to prove if damages actually occurred, only that Pte Manning knew they could.

Pte Manning is alleged to have been the source of a series of high-profile security breaches that saw Wikileaks rise to global fame.

After a video showing US troops firing on Iraqis from a helicopter came caches of documents from both the Iraq and Afghan wars, and a huge haul of classified state department cables.