No End to Appeals

The Karlsruhe-based Federal Constitutional Court said the attempt by Mounir el Motassadeq was inadmissible.

Motassadeq, who was friends with members of the Hamburg-based terror cell involved in the suicide attacks, was found guilty in November of being an accessory to murder in the deaths of 246 passengers and crew on the four hijacked aircraft used in the attacks.

He was sentenced to 15 years in prison by a court in Hamburg on Monday.

But his five-year legal battle is set to continue as his lawyers turn to Germany's Federal Court of Justice to appeal his sentence. His lawyers have also said they may take the case to the European Court of Justice in Luxembourg.

"That will be the last appeal," Motassadeq's lawyer Udo Jacob told news agency AP on Friday.

Jacob added that Friday's decision by Germany's highest court had not impressed him.

"I still think that basic rights have been violated," Jacob said.

Guilty of "immense wrong"

Motassadeq, 32, has claimed throughout the legal saga, which saw him in and out of several courtrooms, he was friends with the hijackers but did not know about their plans.

He was found to have handled bank transfers for members of the Hamburg-based cell, including the presumed ringleader of the attacks, Mohammed Atta, and to have helped cover up their whereabouts.

The sentencing hearing for Motassadeq in Hamburg this week was marked by delays as the Moroccan's lawyers filed a series of appeals to halt the process.

Eventually however the court followed the recommendation of state prosecutor Walter Hemberger who said Motassadeq deserved the toughest sentence possible under German law because he had committed an "immense wrong."

Transatlantic tensions

German authorities have indicated that they will deport Motassadeq to Morocco once he has served his sentence.

Motassadeq's case and the perceived failure of German courts to prosecute him swiftly and successfully have strained Berlin's ties with Washington over recent years.

Motassadeq is only the second man to be convicted of a role in the Sept. 11 attacks. Zacarias Moussaoui, a French citizen of Moroccan descent who received a life sentence from a US court in May 2006, is the only other person convicted for having links to the attacks.