A 15-year-old boy is in a critical condition in hospital after being assaulted in Blackpool.
Police are examining CCTV in a bid to identify those responsible for the attack, which happened on High Street in the early hours of Tuesday.
The teenager was taken to the Blackpool Victoria Hospital but later transferred to the Manchester Children's Hospital. His condition is described as critical.
Lancashire Police said they had begun a major investigation into the incident.
Detectives believe a number of people would have been leaving the nearby Flamingo's nightclub at the time of the attack and appealed for witnesses.
Police family liaison officers have been appointed and are supporting the boy's family.
Det Ch Insp Andrea Barrow, senior investigating officer, said: "We are already speaking to a number of witnesses but I am keen to speak to anyone else who was in the area or who may have witnessed something suspicious to come forward and contact us.
"I know that Flamingo's nightclub would have been emptying at that time so there would have been people out in the street making their way home."