A 16-year-old boy has suffered a broken jaw in an unprovoked attack in Mansfield.
Police say he was with a friend who was also punched by a group of unknown youths in an alleyway on the Bull Farm estate at around 7.30pm on Friday.
He was taken to hospital where he underwent surgery on his jaw.
The other victim did not need hospital treatment.
CCTV and witness enquiries are ongoing and officers are appealing for anyone who witnessed the incident to contact 101 or Crimestoppers, anonymously, on 0800 555 111, quoting incident number 869 of 15 June 2018.