Member of a German police anti-terror unit
Member of a German police anti-terror unit Getty Images

German authorities raided a mosque in Stuttgart that is allegedly supporting Isis as well as a number of addresses in Berlin as part of anti-terror operations.

Police seized computers, data storage devices, smartphones and documents from the Islamic Educational and Cultural Center Mesdschid Sahabe in the southwestern city of Stuttgart, said interior minister of Baden Wurttemberg state Reinhold Gall.

Two apartments were also searched in Berlin's Neukölln and Friedrichshain areas. Prosecutors said residents in the flats were suspected of planning a terrorist attack and possessing illegal weapons. A laptop, air gun, and other objects allegedly contravening weapons prohibition laws were found, Germany's DPA press agency reported.

A picture of one of the flat's 28-year-old residents posing with an AK-47 and declaring his desire to fight in the Syrian civil war were allegedly posted online by an anti-Isis Syrian group, leading to the raids, reported Bild.

Gall said ten people have travelled to Syria to fight for Isis after visiting the Stuttgart mosque, which allegedly collected donations for terrorist groups and fighters.

"The association supports, in the form of the so-called Islamic State, an Islamist group that carries out religiously-motivated attacks against persons and property," he said as quoted by AFP.

In North Rhine Westphalia on Thursday, police arrested a 31-year-old man at a refugee centre on suspicion of belonging to terrorist organisation Isis.