A large fight involving knives and a machete at a hotel in Adelaide's CBD overnight has left six people in hospital and led to the arrests of two others.
Several victims were "stabbed or assaulted with weapons" during the fight, which is now being investigated as part of a police operation aimed at curbing gang violence.
One person is in a critical condition in the Royal Adelaide Hospital, police said.
Emergency services were called just after 1am on Sunday, and police and paramedics attended the Producers Bar (Old Exchange Hotel) on Grenfell Street where the fight had broken out.
"On arrival, police have found a number of people with severe injuries including stab wounds," Superintendent Matt Nairn said.
Superintendent Nairn said several of the participants were known to police, and that a machete and knives had been seized.
"We've recovered a number of weapons both from within the hotel and on the street," he said.
Police said those taken to hospital included a 24-year-old Devon Park man, and that two men from Adelaide's north had been charged.
An 18-year-old from Munno Para West was charged with affray and disorderly behaviour.
A 22-year-old Paralowie man was also charged with disorderly behaviour, as well as refusing to provide his name and address.
Police have appealed to anyone who filmed the fight, has dash-cam footage or any information to contact Crime Stoppers on 1800 333 000 or online.
Police have said it is too early to tell what sparked the fight, and have refrained from labelling those involved as gang members, but have confirmed an anti-gangs task force is now investigating.
Operation Meld was launched last July, after a spate of violent brawls and crimes in Adelaide's northern and western suburbs.
