Australind police say it took more than two hours to subdue a large out-of-control teenage party in Australind on Saturday night.
Sgt Brett Cassidy said about 10 officers in five police cars were called out to the party on Garfield Street in a bid to move a mob of 100 teenagers.
Sgt Cassidy said it appeared a Facebook invitation sparked a large number of uninvited guests aged 14 to 17 years.
"It was put on Facebook then it appeared everyone got hold of it, then it got out of hand," he said.
"There were five police cars, three from Bunbury and two from Australind."
Sgt Cassidy said the party was hosted by 18-year-olds who called police when the part got out of control.
"Bottles were thrown, none actually hit police cars," he said.
A large number of youths were taken to Bunbury police stations to be collected by their parents.