Police have raided dozens of properties in Germany and arrested a Tunisian man suspected of being a recruiter for Islamic State and rounding up supporters to carry out an attack.

Frankfurt prosecutors said 54 flats, business premises and mosques in the region were searched early on Wednesday.

They said the investigation was directed against 16 people in total, aged between 16 and 46.

The 36-year-old main suspect was arrested in Frankfurt. He is believed to have been a recruiter and smuggler for the IS group since August 2015.

Prosecutors say plans for a possible attack were at a very early stage and no concrete target had been chosen.

In a separate case, prosecutors in Berlin said they arrested three people on Tuesday night suspected of planning to travel to Syria or Iraq to undergo explosives and weapons training with IS.

All three were associated with the Fussilet mosque in Berlin, known as a gathering point for radicals, said Martin Steltner, a spokesman for prosecutors.

Berlin Christmas market attacker Anis Amri visited the mosque shortly before his December 19 rampage in which 12 people were killed.