Police are seeking more information about a school formal that ended in a brawl involving more than 100 youths at Sydney's Darling Harbour.
Up to 130 young people were caught up in the violence in a car-park near the Maritime Museum shortly before midnight.
Police who raced to the scene reported a "large number" of intoxicated young people.
Fighting broke out between local youths and a group of Year 11 students from a north shore high school who had just celebrated their formal, the police said.
Three 17-year-old male youths were taken to Sydney and Royal Prince Alfred hospitals with non-life threatening injuries.
Seven males, aged between 14 and 17, were arrested and interviewed at Surry Hills Police Station.
None of them has any connection with the school and they have been released pending further investigations.
Police are now studying CCTV footage.
Initially the police were told the formal had been on a harbour cruise, but they learned later that it was held at a nearby public building.
Anyone with any information is urged to contact City Central Police or Crime Stoppers on 1800 333 000.
