West Yorkshire Police are looking to identify around 20 people involved in a mass brawl in a Leeds bar.
Dramatic CCTV footage shows groups of young men clashing in the Headingley establishment as arms, legs, chairs and chairs flew across the bar floor.
Two security guards did their best to break-up the fracas but they were unable to diffuse the booze-induced fury spilling over in the nightspot.
One man was kicked several times as he lay on the floor.
Later, a 28-year-old man who was found with a wound to the head and later treated at hospital.
"The situation appears to have started with a confrontation between two people that has then quickly turned in to a mass brawl," said Detective Inspector James Entwistle.
"These were some very ugly scenes where people were punched, kicked and stamped on and glasses and chairs were thrown.
"The video shows how there was very little that the bar's security could do to control the situation and it was clearly a shocking thing for staff and other people in the bar to witness.
"We are treating this as an incident of violent disorder and are carrying out enquiries to identify those involved. We do have very clear CCTV footage that captures the whole incident and are working through that in detail to identify the main suspects.
"We would like to hear from anyone who knows the identity of any of those shown fighting in the clip we have released or who recognises themselves as a witness."
A 21-year-old man has already been arrested on suspicion of violent disorder and has been released under investigation.
Anyone with further information is asked to contact Detective Constable 6722 Craig Mason via 101 quoting crime number 13180079662 or call the independent charity Crimestoppers anonymously on 0800 555 111.