Police were pelted with bottles as they tried to break up a knife fight at an out-of-control birthday party in Perth's southeast.
Police attended a house in Queens Park just before 9pm (WST) on Saturday after reports of a mob fighting with knives at the front of the house.
Those allegedly fighting evaded police by running to the back of the property.
The 15th birthday party, which had about 200 guests, was declared an out-of-control gathering and everyone was told to leave.
But police had to withdraw down the street as bottles were thrown at them.
Mounted police and the dog squad were used to help remove the unruly revellers.
Move-on notices were issued to a number of people and a 19-year-old man will be summonsed for disorderly conduct, police said.
Investigations are continuing, with other vehicles in the area also having windows smashed.
