Several explosions have rocked Manchester Arena, in northern England, at the end of American Ariana Grande gig Monday night.
The number of casualties is yet unknown, but multiple reports said several people died while many were injured. It was not clear whether the blasts were the handiwork of terrorists.
Video footage showed people fleeing in tears from the venue after bangs rang out immediately after the concert finished.
Bloodied concertgoers were pictured being helped by emergency services outside the gig and armed police were seen patrolling the arena.
Evie Brewster, who attended the concert, told MailOnline: ‘Ariana Grange had just finished her last song and left the stage when a huge explosion sounded.
‘Suddenly everybody started screaming and running for the exit.
Police said they were responding to reports of an explosion and that there were a number of confirmed casualties and others injured, Reuters reported.
“We were making our way out and when we were right by the door there was a massive explosion and everybody was screaming,” concert-goer Catherine Macfarlane told Reuters.
“It was a huge explosion — you could feel it in your chest. It was chaotic. Everybody was running and screaming and just trying to get out.”
A spokesman for Ariana Grande’s record label said that the singer was “okay”. A video posted on Twitter showed fans screaming and running out of the venue.
Britain is on its second-highest alert level of “severe” meaning an attack by militants is considered highly likely.
Manchester Arena, the largest indoor arena in Europe, opened in 1995 and has a capacity for 21,000 people, according to its website. It is a popular concert and sporting venue.