AMSTERDAM, Sept 22 (Reuters) - 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 following 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 for the event for most of the week. ||||| Police officers were attacked and cars were set alight when a sweet 16 birthday party in the Netherlands turned into a nightmare. The Facebook invite, which was meant to be a private affair, became a party of thousands. NBC's Duncan Golestani reports. 
 
 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. 
 
 A teenager's birthday party in a small Dutch town got out of control when the invite went viral. NBC's Duncan Golestani reports. 
 
 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. 
 
 Catrinus Van Der Veen / AFP - Getty Images Chairs burn in the northern Dutch town of Haren late on Friday after thousands of party-goers showed up to a teenager'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. 
 
 Catrinus Van Der Veen / AFP - Getty Images Hundreds of youths gather in Haren, northern Netherlands, on Friday. Dutch mass-market daily De Telegraaf reported that tens of thousands of people received a Facebook invitation to a schoolgirl's birthday party. 
 
 NBC News' Nanette van der Laan and Reuters contributed to this report. 
 
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– Oh, the importance of privacy settings. A Dutch girl sent out an invite via Facebook to her 16th birthday party, which ended up getting viewed by about 30,000 people. Last night, a crowd estimated at 3,000 showed up in the small town of Haren, and the ensuing vandalism, looting, and clashes with riot police left six people hurt and 20 arrested, reports the BBC and Reuters. Many sported "Project X" T-shirts, a reference to the movie about a party that gets out of hand, reports NBCNews.com. The birthday girl "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," a local police official says. Facebook, though, might be able to help undo the damage: A new "Project Clean-X Haren" page sprang up after the unrest and already has more than 23,000 likes.