BERLIN  The German Interior Ministry ordered simultaneous raids in three states on Tuesday against what it called Salafist networks suspected of seeking the imposition of an Islamic state. The action signaled growing concern over the radical messages of some Islamic groups.

The raids, in Bremen, Lower Saxony and North Rhine-Westphalia, were not linked to a recent terrorism alert reportedly inspired by phone calls from a man who said he wanted to quit working with terrorists and who warned of a pending Mumbai-style attack, the Interior Ministry said.

The ministry statement said the raids were directed at two groups: Invitation to Paradise in the cities of Brunswick and Mönchengladbach, and the Islamic Culture Center of Bremen, on the North Sea coast. The two groups work closely together and share the same ideology. The authorities are seeking to outlaw both groups.

The raids appeared to represent a departure for the German authorities in their dealings with radical Muslim groups. They were conducted under the authority of postwar laws enacted with an eye to the Nazis to prevent the overthrow of the state or Constitution by extremist groups. Before, those statutes had been invoked primarily against right-wing nationalist and neo-Nazi groups, and German intelligence had focused primarily on individual Muslim extremists rather than groups.