Three people were taken to hospital after being stabbed in the street during the early hours of the morning.
The attack happened at roughly 4.30am on Saturday in Lenton Boulevard, Nottingham.
No one has been arrested in connection with the serious assault but police are investigating.
Lenton Boulevard has been shut by Nottinghamshire Police between Ilkeston Road and Derby Road.
Local resident Saundra Timothy heard the sirens during the early hours.
The 50-year-old said: “I hope the police resolve this soon because it looks quite serious.
“I thought nothing of the sirens because there are often police cars flying about over the weekend.”
Last Month Nottinghamshire was named as one of the worst places in England for people being caught with knives.