A Moroccan convicted as an accessory to murder in the Sept. 11, 2001, attacks was sentenced Monday to the maximum 15 years in prison.

A German appeals court had convicted Mounir el Motassadeq, a friend of three of the suicide pilots, of the charge in November and sent the case to a state court in Hamburg for sentencing.

The Hamburg judges followed the recommendation of federal prosecutors, who said el Motassadeq deserved the maximum penalty because he had known that the hijackers intended to use planes to stage attacks.

Defense lawyers, who insisted the 32-year-old should be acquitted, said they may appeal to a European court.

In November, a federal appeals court ruled that judges in Hamburg had wrongly acquitted el Motassadeq in 2005 of direct involvement in the attacks, even though they sentenced him to seven years in prison for belonging to a terrorist group.

The appeals court convicted el Motassadeq as an accessory to the murder of 246 passengers and crew members aboard all four jetliners used in the attacks, and ordered the Hamburg state court to set a new sentence.

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El Motassadeq was a close friend of pilots Mohamed Atta, Marwan al-Shehhi and Ziad Jarrah when they lived and studied in Hamburg. He has acknowledged training at an Al Qaeda camp in Afghanistan and that he was close to the three hijackers, but insists he knew nothing of their plans.

The federal appeals court said evidence showed el Motassadeq knew that the hijackers planned to hijack and crash planes. It found that his actions — transferring money, and helping the hijackers keep up the appearance of being regular university students by paying tuition and rent fees — facilitated the attacks.

The federal court also said it was irrelevant to el Motassadeq's guilt whether he knew of the plot's timing, dimension or targets.

El Motassadeq was convicted and sentenced to the maximum 15 years in prison in 2003, but that verdict was overturned by a federal court the following year — largely because of lack of evidence from Al Qaeda suspects in U.S. custody.

At a retrial that resulted in the 2005 conviction, the U.S. provided limited summaries from the interrogation of, among others, Ramzi Binalshibh, a suspected liaison between the Hamburg hijackers and Al Qaeda.