Witness: Suspect Part of Sept. 11 Terror Cell

The testimony came just days after US authorities had released transcripts of interviews with Ramzi Binalshibh, the alleged organizer of the Sept. 11 attacks. Binalshibh had exonerated Mounir el Motassadeq, saying that the Moroccan had no knowledge of the terror plans.

But on Tuesday, Shahid Nickels, a 23-year-old German student, said Motassadeq belonged to the inner circle of a radical group promoting attacks against the US and Israel.

Nickels said he met Motassadeq and the others in 1997 at Hamburg's radical al-Quds mosque, where he attended a Quran study class led by Mohammed Atta, the alleged leader of the attacks, AP news agency reported.

According to Nickels, the group believed that "Israel didn't have the right to statehood and suicide attacks were legitimate. In America, they believed that the Jews had a lot of power."

He said that by late 1999, the group's conversations were "all about jihad."

"They said that something had to be done against America," said Nickels, the first of more than 30 witnesses scheduled to appear at the trial, according to AP.

Motassadeq is on retrial after a German appeals court overturned a 2003 conviction in an earlier trial. He had been serving a 15-year sentence for his involvement in the attacks, but was released from prison in April pending his retrial.

Nickels' testimony during the first trial had played a crucial role in convicting Motassadeq. On Tuesday, he said that he distanced himself from the group.

"I couldn't stand hearing any more about the guilt of the Jews," Nickels said.