The United States will not allow German judges to question al-Qaeda prisoners in the retrial of a September 11th suspect, a Hamburg court was told today.
The decision casts doubt on the prospects for the new proceedings against Mr Mounir El Motassadeq, (30), who is charged with plotting the 2001 attacks alongside Mohamed Atta and others, and with membership of a terrorist organisation.
In a letter to the German embassy in Washington, read out in court, US authorities said they had to protect the sources and methods of the security services.
The letter said that "interactive access" to such prisoners could hamper their interrogation and lead to critical secret information, including about terrorist threats, being divulged.
In February 2003, Mr Motassadeq became the first person anywhere to be convicted in connection with the September 11th attacks and was sentenced to 15 years in jail.
But in March this year a higher court ruled the verdict was unsatisfactory as judges had not had access to testimony from Ramzi bin-al Shaibah, a key member of the al-Qaeda Hamburg cell who was captured in Pakistan in 2002. It ordered a new trial.
The German authorities asked the United States in May to give them access to six key witnesses including bin al-Shaibah, but the US letter said that even information on whether a given individual was in custody was classified as secret.
It said it was not possible for the United States to confirm whether the persons named, who also include top al-Qaeda figure Khalid Sheikh Mohammed, were in US custody or not.
As well as evidence from bin al-Shaibah, Germany has asked for testimony, either directly or in writing, from suspected September 11th plotter Zacarias Moussaoui and former CIA head Mr George Tenet.