'Yes, I am the 20th hijacker'

In an emotional courtroom outburst the man branded the "20th hijacker" pledged his allegiance to Osama bin Laden, said he was a member of al Qaeda and claimed he had "certain knowledge" of the 11 September attacks.

Despite this, a US judge refused to accept a guilty plea from Zacarias Moussaoui, the only person so far charged in relation to the terrorist attacks on the US.

Judge Leonie Brinkema gave the defendant a week to reconsider his plea. Moussaoui, a 34-year-old French citizen, is indicted on six counts of conspiring to commit acts of international terrorism. If convicted, he faces the death penalty.

Representing himself in the Virginia court, he said: "I don't need a week. I've been thinking about it for months."

The case continues.