Police are investigating an incident at Broadfield Barton, Crawley, on Sunday evening (12 January) in which a 19-year-old man sustained knife wounds during an altercation involving several other young men.
The attack happened shortly before 7.30pm and the victim was taken to hospital after he suffered serious injuries but not life-threatening injuries.
Three people have been arrested - a 26-year-old man on suspicion of wounding with intent; a 19-year-old man on suspicion of possessing a bladed article in a public place and a boy aged 16 on suspicion of causing grievous bodily harm with intent.
The 26 and 16-year-old remain in police custody and the 19-year-old man has been released on police bail until 13 February.
Investigating officer Detective Constable Elliott Whitehead said: "We are appealing to anyone who may have witnessed the assault or has CCTV, dash cam or mobile phone footage of the incident to make contact with us.
"We have a dedicated response to reduce instances of knife crime and serious violence and there will be an increase in high visibility patrols in this area. Please approach officers if you would like to raise any concerns you have or if you think you can assist with the investigation.
"Alternatively you can contact the independent charity Crimestoppers anonymously, telephone 0800 555111."
You can report information to us either online or call 101 quoting Operation Dalmatian.