Berlin police say they are raiding a mosque after the arrest of two people suspected of belonging to an Islamist extremist group.

Police spokeswoman Patricia Braemer said the two suspects were arrested before the raid of the mosque Thursday in the city's western neighborhood of Charlottenburg. She did not give any further details on the suspects or the raid because the search was still ongoing.

In September, Berlin police raided eight buildings after a months-long investigation into suspected Islamist extremists involved in violent activities. Police said at the time there was no evidence that suspects had been involved in planning attacks in Germany.