Three people were injured when a mass brawl involving about 40 people broke out at a boxing event in Leeds, police have said.
The fight erupted at Elland Road's Centenary Pavilion, on Saturday night, causing the event to be called off.
Footage of the brawl shows chairs being hurled across the venue and a woman being knocked to the floor.
West Yorkshire Police said it was investigating the "large-scale disorder". No arrests have been made.
A force spokesman said officers were called at 22:27 GMT.
"Around 40 people were involved in the disorder at an organised boxing event at the stadium," he said.
"Officers attended and the crowd dispersed. Three people suffered minor injuries and were taken to hospital."
Writing on Facebook, event organisers Golden Gloves Boxing League said: "I'm so sorry to announce the Main Event has been called off, due to crowd trouble."
Promoter Danny Morgan later said he had 22 security staff on duty and the event had been "absolutely brilliant until that trouble broke out".
He added: "It takes months to put something like this together; people have no idea how much time, effort and money it takes to set this up."
A spokesperson for Leeds United FC said the club was "disgusted by the violent scenes" and was working with police to identify those involved.