There have been violent clashes between protesters and police in the German city of Rostock, following a largely peaceful demonstration against next week's G8 summit in a nearby town.
Protesters threw stones and bottles and attacked police officers with sticks. Several people were arrested.
There were no details of injuries.
Police said there were up to 500 potential troublemakers among the estimated 20,000 people who gathered in Rostock to protest.
The summit is due to begin on Wednesday in the nearby resort town of Heiligendamm.
Approximately 13,000 police officers were drafted in to provide security.
