At least 60 people were injured on Saturday in a crowd surge at a concert organised to mark the switching on of Birmingham's Christmas lights in the city centre, emergency services said.
X-Factor runners-up JLS had just finished their set at Millennium point, when a metal crash barrier penning the crowd in failed, leaving scores needing treatment, West Midlands Ambulance Service said.
Four people were taken to hospital and one sustained multiple fractures during the crowd crush, it said.
The event, which had been due to feature other top bands including the Sugababes, was subsequently cancelled. Paramedics set up a special unit to treat the injured at the scene.
According to Birmingham City Council many thousands more than the 5,000 fans expected at the event turned up.
Some estimates put the total at 27,000 by the time the band JLS had finished their set.