Anti-globalisation activists have rioted for a third consecutive night in Hamburg even with Group of 20 leaders having already left the northern Germany city.
Police again used water cannon trucks against rioters attacking them with iron rods and pavement blocks early Sunday evening.
They arrested 186 protesters and temporarily detained another 225 people.
Officials said 476 officers have been injured in the violence since Thursday. The number of injured protesters wasn't clear.
German Foreign Minister Sigmar Gabriel condemned the violence, saying, "Germany's reputation is severely affected internationally by the events in Hamburg."
Gabriel told Bild am Sonntag a Europe-wide investigative team should search for suspects.
The overwhelming majority of the tens of thousands who took to the streets protested peacefully against the G20 summit.