Mounir al-Motassadeq awaits the start of his hearing at a court in Hamburg Jan. 5, 2007.(Xinhua Photo/AFP)  Photo Gallery >>>

     BERLIN, Jan. 5 (Xinhua) -- Defense lawyers of Mounir al-Motassadeq, the first man convicted of a role in the Sept. 11 terrorist attacks on the United States, called for a halt to new sentencing hearings started Friday.

    The two German lawyers challenged the authority of the Hamburg court, which started the hearings meant to increase Motassadeq's current seven-year prison term to 15 years.

    Motassadeq, a Moroccan, who had received Al-Qaeda training in Afghanistan, was sentenced in August 2005 for knowing his fellow Islamists' plan though he did not take part in the suicide act.

    He had been studying electrical science in Germany, where he became friends in 1999 with Mohammed Atta and other suicide hijackers.

    The Hamburg state superior court would not query the conviction this time but only consider the sentence after two trials and two appeals.

    Motassadeq's main lawyer criticized judges of the state superior court of arbitrarily selecting a panel of three from among themselves to try the case, saying the court was extraordinary and banned under the German constitution.

    The other lawyer, Udo F Jacob, has filed an appeal to Germany's constitutional court, which does not normally try crime appeals, demanded the Hamburg court wait for the result.

    Federal prosecutor Walter Hemberger insisted that all the three Hamburg judges were qualified to try Motassadeq, saying the constitutional appeal would have no chance of success.

    Presiding judge Carsten Beckmann said the trial would proceed while the challenges were considered separately.