Wiltshire Police are appealing for witnesses to a disorder which occurred in the area of Delamere Drive, Swindon.
At approximately 7pm on Friday 15 June, a disorder took place in the alleyway in Delamere Drive which leads to the play park.
It then continued into the surrounding areas.
A 13-year-old girl sustained swelling to her jaw and eye during the incident.
PC Jo Field said: “A number of youths were involved in this incident, as well as adults, and we are keen to hear from anyone who may have witnessed the disorder, or saw those involved before or after the incident.
“The young victim is being provided with support and our enquiries are currently ongoing – if you think you have information that could help, please call us on 101 and quote crime reference number 54180054505.”
Alternatively, information can be left with Crimestoppers anonymously on 0800 555 111.