Police in the German city of Stuttgart have said 20 people were arrested and four police officers injured after a drugs check in the city centre sparked attacks on officers and police vehicles and widespread vandalism of stores.
The disturbance started as an apparent reaction to the police's search for drugs, as groups of people partied in a central park late on Saturday night.
According to German TV reports, people then attacked store fronts in a nearby shopping street, tearing up paving stones and smashing store windows.
