Zurich police are looking for suspects after a spontaneous party turned violent over the weekend.

Hundreds of young people gathered near the Mythenquai on the shores of Lake Zurich, after an SMS, or text message, called for an impromptu party.

Police also received the message, leading to a meeting with some young people throwing rocks and bottles, and having torched a number of dumpsters.

Just four months ago Zurich introduced a program to grant permission for outdoor parties, hoping to avoid such spontaneous gatherings.

Though police admit this event would not have been approved.