A party at a Brighton squat descended into a mass brawl after a man reportedly broke in using an axe.
Police were called to the disused shop in Vantage Point, New England Road, in the early hours of Saturday morning.
When they arrived at about 3.30am, about 100 people were inside, and a fight had broken out.
One of the partygoers, Jamie Leatham, said: “The group had previously been refused entry to the private party, held at a squat near Preston Circus, but returned with weapons and smashed their way through the glass storefront with bricks and other missiles, injuring several partygoers due to broken glass.
“People attending the party panicked when they realised the gang was heavily armed, causing a crush at the exit as they tried to escape.”
He added: “This was a private party in a legally squatted premises. There was no police presence or trouble of any kind, no noise complaints, before all the drama.”
A police spokeswoman said: “Police quickly attempted to restore order for the safety of those attending the party, which was met with some resistance and three men were subsequently arrested for public order offences.
“Police are viewing CCTV, conducting house-to-house enquiries and an axe recovered from inside the building is being forensically examined. Police are appealing for anyone with information to come forward.”
A 36-year-old man, a 44-year-old man and a 25-year-old man, all of no fixed address, have each been arrested on suspicion of public order offences and released on bail pending further enquiries until Tuesday, 19 April.
Anyone with information is asked to contact Sussex Police on 0845 60 70 999 quoting serial 292 of 5/3 or anonymously to the independent charity Crimestoppers on 0800 555 111.