BERLIN (Reuters) - German police on Tuesday raided more than 20 sites in Berlin with links to a mosque visited by a Tunisian asylum seeker who killed 12 people in an attack on a Christmas market in December.

Anis Amri, the Tunisian suspect of the Berlin Christmas market attack, is seen in this photo taken from security cameras at Brussels North train station, Belgium, December 21, 2016. Federal Public Prosecutor's Office/Handout via Reuters.

In the raids, which began at 0500 GMT, some 450 officers searched apartments, two companies’ premises and six prison cells connected to an organisation called “Fussilet 33 e.V.”, which ran the mosque, the police said in a statement.

“The cause for these raids is the fact that Berlin’s state interior ministry has issued a ban against the ‘Fussilet 33’ organisation,” Berlin police spokesman Winfrid Wenzel said.

The Tunisian Anis Amri killed 12 people and injured dozens more on Dec. 19 by driving a truck into a crowded festive market in Berlin. [nL5N1EE5EG] Amri, who pledged allegiance to Islamic State, was shot dead by Italian police in Milan four days later.

Andreas Geisel, interior minister for the state of Berlin, told a news conference that Amri had regularly visited the mosque run by “Fussilet 33 e.V.” including on Dec. 19, only an hour or so before attacking the Christmas market.

The mosque has now been shut down, but Geisel said this was not only because of the Amri connection. Some senior members have been charged or already sentenced for supporting terrorist organisations abroad and preparing acts of violent subversion against the state, he said.

Geisel said Berlin was a cosmopolitan and tolerant city that welcomed people who are persecuted in their home countries or whose lives are in danger, and that should remain the case.

“But people who come here to carry out violent acts or preach violence or who, from Berlin, support organisations that carry out Islamist terrorism in countries like Syria and Iraq or collect money for that, train fighters for jihad, organise trips to these areas and recruit fighters for Islamist terrorism, are not welcome here,” he said.

Geisel said there had so far been no indications that members of the mosque organisation were planning further attacks in Berlin.

On Jan. 31 German police arrested three men on suspicion of having close links to Islamic State militants and planning to travel to the Middle East for combat training. Newspaper Bild reported that those men were frequent visitors at a mosque in the Berlin district of Moabit that Amri also used to visit. [nL5N1FL7DW]