Queensland police officers were forced to drag two injured colleagues into a Brisbane council bus after they were attacked with bricks during an out-of-control party in the city's south.
One of the male constables required eight stitches while the other was given four stitches and will need plastic surgery for a fractured eye socket.
Detective Inspector Geoff Acreman said the attack came after police were called in to break up a party in Acacia Ridge on Saturday night.
Up to 250 people, some as young as 11, turned up at the party after it was advertised on Facebook.
Insp Acreman said although police managed to break up the party by 11pm a group of youths congregated at a nearby bus stop.
Several boarded a bus when it arrived and one started kicking out its windows from the inside while others were damaging it from the outside, he said.
Police also boarded the bus to arrest the youth when the two constables outside were hit in the head by bricks that were ripped off a nearby wall and hurled at them.
"The officers on the bus decided to drag those two officers who had fallen onto the bus and directed the bus driver to shut the doors and drive the bus from the area," Insp Acreman told reporters.
He said police were yet to ascertain why the youths were being so violent.
No one had yet been charged by Sunday afternoon, but police were following several leads, he said.
The inspector said the incident should serve as a reminder about the dangers of advertising parties on Facebook.