German authorities raided homes and religious schools connected to two radical Islamist groups with suspected terrorist links on Tuesday morning, the Interior Ministry said.
The raids, in the western cities of Moenchengladbach, Braunschweig and Bremen, were aimed at Salafist groups Invitation to Paradise and Islamic Culture Center Bremen, ministry spokesman Stefan Paris said in a statement.
The two are suspected of "wanting to create an Islamic theocracy and working against the democratic order of Germany," he added.
"It is necessary and important not to wait for a militant struggle in form of jihad before intervening against unconstitutional groups," Paris said.
A security official, speaking on condition of anonymity in line with department policy, said dozens of private homes were searched, as well as religious schools and a store belonging to Invitation to Paradise that sells face-covering veils for women and caftans for men.
Police said they seized evidence during the raids, but would not comment further.
The searches are part of a long-term strategy to ban the two groups which work closely together and share the same Salafist ideology, the security official said.
Salafism has often been linked to terror plots and seeks to revive strict Muslim doctrine dating back to the era of the 6th century Prophet Muhammad. "Not every Salafist turns into a terrorist, but we know that future terrorists have almost always visited Salafist workshops and schools," the intelligence service of the state of Lower Saxony, where the searches focused on Invitation to Paradise in the city of Braunschweig, said in a 2009 report.
Intelligence services say they have been watching the groups for several years. They have regularly featured in annual reports. In online videos, Invitation to Paradise has called for the execution of secular Muslims, demanded women never leave their homes without male chaperones and said people who have sex before marriage will go to hell.
It has in particular attracted young Muslim immigrants and German converts.
The Interior Ministry said Tuesday's raids were not related to the current terrorist threat to Germany. Germany upped its terror alert on Nov. 17, warning of an increased threat from Islamic extremists.
Germany's Federal Criminal Police office says it has "concrete evidence" that 70 German converts and young immigrants have traveled to Pakistan's lawless border region for terrorism training in recent years, and about a third have returned to Germany.