KARLSRUHE, Germany -- German authorities launched a search operation in the northern city of Hamburg early Wednesday for eight suspected terrorists, the federal prosecutor in Karlsruhe said.

Police raided homes and a bookshop in Hamburg in search of the eight, who are accused of working together to foster "aggressive militant Islamic fundamentalism", Federal prosecutor Kay Nehm said.

Nehm said six people were being questioned but it was unclear whether any of them were among the eight, who police said come from Afghanistan, Egypt and Morocco and are aged from 28 to 51.

Nehm said no connection could be made between the eight and the September 11 attacks on the United States based on investigations so far, AFP reported.

However a Hamburg police spokesman said one of them had been in contact in the past with Mohammed Atta, the alleged mastermind of the attacks.

The police also said that a seventh person was expected to be questioned soon in Italy, without giving further details.

The prosecutor said the search operation was concentrated on six homes near the Al-Qods Mosque in Hamburg and a city bookshop where the group was believed to have met.

some 3,000 people were killed when 19 hijackers commandeered four passenger planes to fly into targets in the United States on September 11.

Two destroyed the World Trade Center in New York, while one hit the Pentagon near Washington and the fourth crashed into a field in Western Pennsylvania after passengers overcame the hijackers.

Three of the hijackers, including Atta, lived and studied in Hamburg for years without coming to the attention of the authorities.