Two men are critically ill after five people suffered stab or slash wounds in a fight at a Great Gatsby-themed New Year's Eve party.
Police were called to Crystal Bar, on Carver Street in Sheffield, at around 2.20am on Monday following the altercation.
Two men were left with life-threatening injuries and remain in hospital in a critical but stable condition. Three other men suffered superficial injuries.
South Yorkshire Police said: "On officer arrival, five men in their 20s were taken to hospital where three of the men were found to have superficial injuries.
"Two of the men suffered life-threatening injuries and remain in hospital in a critical but stable condition.
"An investigation is in its early stages and officers remain in the Carver Street area carrying out inquiries."
An invite to the event said guests would be welcomed with a Prosecco and canape reception to "the biggest party of the year".