The only person charged in the US in connection with the 11 September 2001 attacks has been removed from court at his trial in Virginia.
Moussaoui denies knowledge of the 11 September attacks
Zacarias Moussaoui, often a volatile figure in court, said: "I am al-Qaeda", and described the trial as "a circus".
The outburst came at the start of the selection process to find 12 jurors who will decide the defendant's sentence.
The 37-year-old Frenchman has pleaded guilty to six charges linking him to al-Qaeda's plans to attack the US.
With the first group of potential jurors in the courtroom, Moussaoui told the judge that he wanted to be heard.
When informed that this was not the time for that, he went on to say his American lawyers did not represent him.
Moussaoui has ignored lawyers' advice and will be representing himself.
The 12 jurors, being selected from a pool of 500 people from suburban northern Virginia, will have to decide if Moussaoui should face life in prison or the death penalty.
Each of the potential jurors are being questioned on their knowledge of al-Qaeda and their personal experiences of 11 September.
Four groups were called to the courtroom on Monday to fill in questionnaires made up of 89 questions from the prosecutors and 306 recommended by defence lawyers.
The BBC's Daniela Relph in Washington says finding a neutral jury will be difficult.
It is an area with a large population of military and government workers and it is just a few miles from the Pentagon, where 184 people were killed on 11 September 2001.
The selection process is expected to take one month. The trial is scheduled to start on 6 March.
Moussaoui was arrested at a flight school in Minnesota a month before the attacks. He has admitted that he was planning to fly a plane into the White House, but insists he knew nothing of the wider 11 September plot.
He has told the authorities that he was due to be part of a second wave of attacks.