A 21-year-old man is in a critical condition in hospital after suffering serious head injuries after falling from a balcony during a gig by American punk band A Day To Remember.
The group had been onstage for about 30 minutes when the incident happened at the Guildhall in Portsmouth, Hampshire, at about 10pm last night.
Fans at the concert said the band stopped playing immediately and it was announced that the gig was over, while barriers were put around the injured man who was attended to by St John Ambulance personnel until paramedics arrived.
A Day To Remember posted on Twitter: "Our thoughts are w/ the person who was injured at the show tonight in Portsmouth. Sorry we had to cut the set short due to the circumstances"
One fan at the event, Karl Braham, also posted: "Seeing the guy fall at @whereisADTR can kinda shake you up hope the guy is ok"
Some fans suggested on Twitter that the man had jumped from the balcony and a police spokesman said they were carrying out inquiries to establish the circumstances surrounding the fall.
A Hampshire police spokesman said: "Hampshire Constabulary was called at just after 10.15pm on Wednesday, November 12, to a report of a man seriously injured at Portsmouth Guildhall.
"The venue was evacuated to allow officers to take statements and establish what happened. The incident is not being treated as suspicious and no witness appeal is required at this time.
"A 21-year-old man from Southsea was taken to Southampton General Hospital for treatment where he remains in a critical condition this morning."
A South Central Ambulance Service spokeswoman said: "We were called at 10.13pm with a report that a male had fallen from a balcony. We sent a response car and an ambulance. His condition was serious and he was taken to Southampton General Hospital."