The only man ever jailed over the 11 September attacks has been released from custody in Germany pending his retrial.
Moroccan Mounir El Motassadeq was sentenced to 15 years in jail last year for conspiring to murder around 3,000 people in the 2001 plane attacks in the United States.
However, he won the right to a retrial at Germany's Supreme Court a month ago.
His lawyers argued that new evidence, which secured the acquittal of one of his associates, also made Motassadeq's conviction unreliable.
He has been released from jail, but cannot leave the city of Hamburg and must surrender his passport.