Amsterdam - Riot police broke up crowds of youths who turned violent in a tiny Dutch town late on Friday after several thousand people descended on the community after a schoolgirl's Facebook invitation to her sixteenth birthday party went viral.

Media reports said six people were hurt, including three seriously, after disturbances broke out in the quiet 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.

Pictures from the scene showed party-goers wearing T-shirts with "Project X" written on them -- apparently a reference to the movie Project X, in which three high school seniors throw a party that gets out of control as word spreads.

Some 30,000 people received the invitation from a girl announcing her 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.

© Agence France-Presse/Getty Images/Catrinus Van Der VeenHundreds of youths gather in Haren, northern Netherlands, on Friday. Tens of thousands of people received a Facebook invitation to a schoolgirl's birthday party.
"She posted the invitation on Facebook and sent it to friends, who then sent it to other friends and soon it spread like wildfire across the Internet," Melanie Zwama, Groningen police spokeswoman told the AFP news agency according to the BBC.

A Twitter account was set up to promote the event, and the Dutch Daily News identified a video posted on YouTube that also promoted the party.

Dutch DJs Yellow Claw and Afrojack -- who each have thousands of Twitter followers -- posted messages about the party on their accounts (in Dutch).

Reports said up to 3,000 people showed up in the town of 18,000.

Haren had been bracing for the event for most of the week.

NBC News' Nanette van der Laan and Reuters contributed to this report.