BERLIN – German authorities on Tuesday banned an organization that they said was a “hot spot” for Islamic extremists and searched a mosque that the group runs.

The “German-speaking Islam Group Hildesheim,” known by its German acronym DIK, had long been on authorities’ radar as a magnet for radicals. The domestic intelligence agency put it under investigation and the mosque was raided in July — yielding evidence that helped lead to the ban.

Authorities say that Muslims were radicalized by the organization and prompted to travel to Iraq and Syria to join the Islamic State group. They have said that there were calls for “hatred toward infidels” in sermons and seminars.

More than 400 police officers were deployed early Tuesday to raid the mosque in the northern city of Hildesheim and the apartments of eight people connected to the organization.

The ban sent “a clear signal: our democracy and our state of law do not allow extremists and radicalizers to use the cover of a peaceful world religion to deliberately incite hatred and violence,” said Lower Saxony state’s interior minister, Boris Pistorius.

There was no word on any arrests.