A US judge has ruled that Zacarias Moussaoui, the French citizen facing charges of conspiracy over the 11 September terror attacks, can fire his court-appointed lawyers.

District Judge Leonie Brinkema said a court-appointed psychiatrist's report and comments made by Mr Moussaoui's jailers showed that he was mentally competent to represent himself.

But after making the ruling at a court in the state of Virginia, she added that she thought he was "unwise" to do so.

Moussaoui is due to go on trial in October

Mr Moussaoui had previously announced that he wanted to fire his lawyers, partly because he believed they were part of a conspiracy with the government and the judge to kill him.

Mr Moussaoui is accused of being the "20th hijacker", involved involvement in the planning of the 11 September attacks.

He has been indicted on six counts of conspiring with al-Qaeda terror group leader Osama Bin Laden, those who hijacked airliners and flew them into buildings in New York and Washington, and others.

The judge's ruling that Mr Moussaoui could represent himself came a day after she decided that he would not be allowed to see any sensitive aviation security information during his trial.

The order amid fears that he might pass any information he saw on security and screening procedures on to potential terrorists.

As they prepared their defence, Mr Moussaoui's lawyers had asked for airport procedure manuals for screening passengers and photographs and video pictures from the airports used by the 11 September hijackers.

But prosecutors successfully argued that the information was on the same level as national security information and the release of it would be "detrimental to the safety of passengers in transportation".

So far, Mr Moussaoui is the only person to have been charged in connection with the attacks in which about 3,000 people were killed.

He could face the death penalty if convicted.