A 15-year-old boy is in a critical condition after a street brawl in Luton.
Police were called to reports of "men fighting with weapons" in Saxon Road in the town at 16:50 BST on Sunday.
Bedfordshire Police said seven people had been arrested and officers were "maintaining a presence" in the area, which was still cordoned off.
Six other people are in hospital with serious injuries, including stab wounds, the force said.
Ch Supt David Boyle said: "I want to send a very clear message that we will not tolerate this kind of activity and will do everything in our power to bring those responsible to justice.
"Any kind of activity involving weapons is an absolute priority for the force and we're responding robustly."
Pictures of the incident appeared on social media, and detectives asked for witnesses or people with mobile phone footage to come forward.