Berlin police say they've raided eight buildings after a months-long investigation into a group of suspected Islamic extremists involved in terrorist activities.

Police said Tuesday the early-morning raids included a search of a mosque's office.

They say the central suspects of the investigation are a 51-year-old Moroccan man accused of encouraging others to go to Syria to fight against President Bashar Assad's regime with "militant jihadist groups," and a 19-year-old Macedonian man suspected of taking part in the fighting there.

Police say there was no evidence that the suspects were planning any attacks in Germany, but released no further information.