Riot police have been called into a sleepy Dutch town to contain thousands of party-goers after a teenager's birthday party invite went viral.
Police were pelted with stones, bottles, bicycles, and potted plants when they tried to enter the house in Haren near the northern city of Groningen on Friday, said the Dutch news agency ANP.
Describing a scene of "chaos", ANP quoted local police as saying several people had been injured, two seriously. Four arrests were made, but police said more could be expected after pictures they took were studied.
The police had been on high alert after the schoolgirl posted a message inviting friends to her 16th birthday party on social networking site Facebook, but forgot to mark it as a private event, prompting more than 20,000 replies.
Public television station NOS said up to 4,000 people, the vast majority of them young, had turned up in Haren, which has a population of 18,000.
Cars and doorways were damaged by objects thrown at police blocking the street where the girl lives. Riot police made several charges to disperse the youths trying to get access to the downtown street.
The birthday girl had meanwhile, fled her home earlier in the day. "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.
Several websites have sprung up dedicated to the party and referring to 2012 US teen film "Project X" - about a suburban birthday party getting out of control after an invitation goes viral.
One site referred to Friday's party as "Project X Haren", counting down the seconds to the event and claiming 150,000 people had been invited. It also published the party's address, adding: "By all means bring some friends!"
Previously "Project X" parties have run riot in different parts of the world including Germany, Australia and especially the US, where teens wrecked an unoccupied Texas home, causing damage of up to $100,000.