The claim, made in a court on Friday in course of the trial of a September 11 suspect Abdelghani Mzoudi, contradicts allegations that the plan for the coordinated attacks was made in the German city of Hamburg.
Heinz Fromm, the head of Germany's constitutional police said that Muhammad Atta, an Egyptian who led the attacks, had chosen his co-conspirators from an al-Qaida training camp in Afghanistan.
Mzoudi is charged with accessory to murder in more than 3,000 cases based on the September 11 death toll and membership of a "terrorist" organization.
He has admitted having contacts with the hijackers but has denied the charges.
Prosecutors have claimed he was already involved in the conspiracy in the spring, months before Fomm claimed the team had been assembled.
Mzoudi's lawyers immediately called for the charges against their client to be dropped.
He is only the third person worldwide to be tried over the attacks.
The same Hamburg court sentenced a Moroccan earlier this year to 15 years in prison on identical charges.