Convicted September 11 plotter Mounir El Motassadeq must remain in a German jail for now after his lawyers failed to win his immediate release on the grounds of new evidence from a secret source.
A Hamburg court said today the Moroccan native must stay in custody pending the outcome of his appeal, which will be announced on January 29.
Motassadeq is serving 15 years after being found guilty in February of conspiring with the Hamburg-based al Qaeda cell that planned and helped execute the 2001 attacks on the World Trade Centre and the Pentagon.
He was the first person convicted anywhere in the world in connection with September 11.
Motassadeq's lawyer, Josef Graessle-Muenscher, told Reuters his client was downcast at Monday's news. "He said: 'I really can't bear it any longer. I'm not a ball to be kicked around'."
Motassadeq's team had demanded his immediate release after an unexpected twist last week in the case of his friend and fellow Moroccan Abdelghani Mzoudi, who is being tried in Hamburg on similar charges.
Mzoudi was freed from custody in the light of new evidence that neither he nor Motassadeq belonged to the core Hamburg cell with advance knowledge of the attack plans.
The judge said the evidence - passed on by German investigators - was presumed to come from Ramzi bin al-Shaibah, an al Qaeda leader who was captured in Pakistan in 2002 and is now in US custody.
Mzoudi's trial continues, but independent legal experts say his chances of acquittal have been greatly improved.
Graessle-Muenscher said Motassadeq's appeal, which is being considered by a higher federal court, could result either in the verdict being upheld or in a decision to re-try the entire case in the light of the new information.