AMSTERDAM (AP) -- Thousands of revelers descended on a small Dutch town sparking a riot after a party invitation posted on Facebook went viral, authorities said Saturday.

"Scum ran amok in our town," said Rob Bats, mayor of Haren, 185 kilometers (115 miles) north of Amsterdam.

"An innocent invitation on Facebook for a party led to serious rioting, destruction, plundering, arson and injuries in the middle of Haren," he said.

Bats said an initial analysis showed a core group of rioters "were very violent and well-prepared and deliberately sought confrontation" with hundreds of police who had been dispatched to the town amid fears of trouble.

Dutch media reported that the party originally was planned as a small celebration by a 16-year-old girl but her invitation went viral when she posted it on Facebook.

Some of the people arriving in Haren on Friday wore T-shirts emblazoned with "Project X Haren," a reference to the film "Project X" that portrayed an out-of-control party.

On Saturday, another Facebook group sprang up called Project Clean-X Haren, urging people to help clear up the debris littering the town's streets.