Riot police broke up crowds of youths who turned violent in a Dutch town late on Friday after several thousand people descended on the community after an invitation to a birthday party posted on Facebook, Dutch media reported.
Media reports said six people were hurt, including three seriously, after disturbances broke out in the northern Dutch town of Haren. Reports said shops were vandalized and looted, a car set on fire, and street signs and lampposts damaged before police broke up the crowds.
Up to 600 riot police were on the scene during the disturbances, according to one media report. There were at least 20 arrests, media said.
Some 30,000 people received the invitation from a girl announcing her 16th birthday party on Facebook, according to media reports.
The party was intended to be a small-scale celebration, but the girl did not set her Facebook event to private and the invitation went viral.
Reports said up to 3,000 people showed up in the town of 18,000. Haren had been bracing itself for the event for most of the week.