By forgetting to mark a Facebook party invitation as 'private,' a Dutch teenager inadvertently drew a crowd of thousands to her small town, where riot police struggled to maintain order. The young girl from the northern Dutch town of Haren, which is outside of Groningen, had just wanted to invite a few people to her family's home to celebrate her 16th birthday party. But when she accidently forgot to indicate that the party was private on the Facebook invitation, word spread quickly. After the invitation spread to around 30,000 people, it was clear to the birthday girl - and police - that things had gotten out of hand. The party took on a life of its own once it spread around the web and was dubbed on one site "Project X Haren," in reference to a movie where a house party spirals of control. Police in Haren had anticipated a surge of people to the town of 18,000 and had blocked off the girl's street. The police were proven right on Friday night when around 4,000 'guests' showed up for the party. Riot police deployed Up to 600 riot police were on hand to control the crowds, which consisted mainly of youths. Officers were pelted with stones, bottles and other projectiles. Cars, doorways and gardens of houses sustained damages and fires were lit in the streets. A spokesman for the regional police, Oscar Dros, said in a press conference on Saturday that the riots had been planned to some extent. "Experienced gang leaders from all over the country advanced with immense violence and aggression," he said. Media reports indicated 30 people were injured and 34 arrests were made. The number of arrests could climb as police analyze photos taken from the scene.