An Islamic group accused of spreading violent anti-Semitism on university campuses and establishing contacts with neo-Nazis was outlawed here today, in the third such ban of an alleged extremist organization since the adoption of new anti-terrorism legislation in Germany following the Sept. 11, 2001, attacks on the United States.

As the ban went into effect this morning, police raided 25 locations across the country, including the home of a leader of the group, Shaker Assem, in Duisburg in western Germany. They seized his computer and documents, Assem said in an interview. There were no arrests.

Hizb ut-Tahrir, or the Party of Liberation, was accused by German officials of advocating the destruction of Israel and the killing of Jews. The group's recruitment efforts centered on young Muslims, officials said, raising the specter of the formation of new groups such as the student-led Hamburg cell that spearheaded the attacks on the World Trade Center and the Pentagon.

"The organization supports the use of violence as a means to realize political interests," the German Interior Ministry said in a statement. "Hizb ut-Tahrir denies the right of the state of Israel to exist and calls for its destruction. The organization also spreads extremely anti-Jewish hate propaganda and calls for the killing of Jews."

Assem lectured in the summer of 2001 at the Islamic study group founded by suspected hijack leader Mohamed Atta at the Technical University in Hamburg. Leading neo-Nazis in Germany attended a meeting held by the group at the Technical University in Berlin in October 2002 in which calls for the establishment of a single Islamic state in the Muslim world were mixed with broadsides against the United States and Israel.

"The organization is still more dangerous in that it has also sought contact with the far-right," Interior Minister Otto Schily said today. "It must be quite clear that such organizations have no business in Germany." Radical Islamic and neo-Nazi groups have had frequent contacts in Germany, on the basis of a shared hatred of Israel and the United States.

"This ban benefits the state of Israel and the U.S.A.," Assem said today in an interview. "We try to inform the population in the Islamic world that it is being colonized by the West. The governments of the Arab world are marionettes of the U.S.A. and the West. This action will not stop our work."

Founded in Jordan in 1953 by a Palestinian sheik, the group claims members across the world, including elsewhere in Europe and in the United States, party officials said. Assem said today that the group was particularly strong in Britain.

German officials said most of the party's meetings are held in private homes, but it also distributes political pamphlets at universities, mosques and Islamic centers. The group has had a German language Internet page since 1993 and publishes a quarterly magazine in German, of which Assem is the editor.

Hizb ut-Tahrir also advocates the overthrow of Arab governments and the creation of a single Islamic state that "implements Islam" in all aspects of life, according to the group's literature.

The group is banned in a number of Arab countries, including Egypt, where 26 people, among them three British citizens, are on trial in a state security court for allegedly attempting to revive Hizb ut-Tahrir.

In November, German police raided 27 apartments belonging to members or sympathizers of Hizb ut-Tahrir. Following those raids, Hizb ut-Tahrir denied accusations it was extremist and said it only wanted to restore an "Islamic way of life" in the Muslim world. "We have often said that we have nothing against Jews in general," Assem said. "We fight against the Zionist aggression in Palestine. We distinguish clearly between Zionism and Judaism."

Special correspondent Souad Mekhennet in Frankfurt contributed to this report.

German Interior Minister Otto Schily said he was concerned about Hizb ut-Tahrir's ties with neo-Nazi groups.