Mounir el Motassadeq, the only man worldwide convicted over the September 11, 2001 terrorist attacks in the United States, has been freed by a German court on Wednesday pending a new trial ordered by a federal tribunal.

He was ordered freed on condition that he stay in Hamburg and not be issued a new passport, said Sabine Westphalen, spokesperson for the Hamburg state court. El Motassadeq's whereabouts were not immediately known.

Westphalen said that there was no longer "urgent suspicion" against him on the charge of accessory to murder, leading the judges to approve his release in a closed-doors hearing.

She said, however, that the tribunal had found that there was still "urgent suspicion" of membership of a terrorist organization but that this was legally insufficient to keep him in custody. "He will be released from investigative custody today but not without conditions," Westphalen said.

Motaasadeq was jailed as an accessory to more than 3,000 murders, and for being a member of the Hamburg-based cell which supplied three of the suicide hijackers who carried out the Sept. 11 attacks. He was given a 15-year sentence for the crimes last year.

However, Germany's Federal Criminal Court threw out the verdict, ordering a retrial after the presiding judge at a hearing last month said the evidence against Motassadeq had not been sufficient for a conviction.

Motassedeq's lawyers believe that the sentence could be quashed entirely when the case goes to retrial, saying that there is a possibility that it could collapse on the same grounds as his original conviction due to key evidence being withheld by the United States.

Motassadeq's new trial is likely begin on June 16, but with a different panel of judges than that which convicted him last year.