Twenty-two have been killed and at least 59 people injured following a suspected terrorist bombing during an Ariana Grande concert at Manchester Arena.
Children are known to be among the dead.
It is the worst terror attack in the UK since 56 people were killed in the 7 July London bombings in 2005.
Footage showed thousands of people fleeing the arena in a panic after an explosion ripped through the foyer as people milled out of the arena at 10.33pm.
Eyewitnesses said the explosion was heard outside the auditorium after the artist had finished her show and left the stage.
There was initial confusion on social media as to whether the loud bang could have been gun shots, or even a speaker exploding, but police confirmed the incident was being treated as suspected terrorism as the grim death toll was announced.
Reuters reported that US intelligence sources believe the attack may have been the work of a suicide bomber, although this is unconfirmed.
Casualties were taken to five hospitals throughout the city, with unconfirmed reports from medical staff of ‘”shrapnel like injuries” being treated and of nuts and bolts found on the ground outside the arena.
Concert goer, Josh Elliot, told the BBC there was pandemonium and confusion as people tried to flee the scene, some reportedly covered in blood and many in tears.
He said: “She finished her last song .. and we heard like a really basey bang, and all I can remember is just everyone … was just running out… people were covered in blood, some people were having a fight, it was quite scary.”
One fan leaving the concert described how the bangs ripped through the arena, which has a capacity of 21,000. It is not known how many people were attending the concert, but the majority of the American pop star’s fans are young females in their teens and twenties.
“The lights came on after the gig and people were starting to leave. As I turned to the left there was an explosion. It was about 40ft behind us near one of the exits. We just thought it was people messing about then it happened again. Another explosion sounded.
“Then we saw the smoke. Everyone just fled. Some people were injured. We saw blood on people when we got outside. People were just running all over the place.
“People have said it was a speaker or balloons but it wasn’t. It was explosions.
— eNCA (@eNCA) May 23, 2017
Majid Khan, 22, said: “I and my sister, along with a lot of others were seeing Ariana Grande perform at Manchester Arena, and we were all exiting the venue when around 10.40-10,45pm-ish, a huge bomb-like bang went off that hugely panicked everyone and we were all trying to flee the arena.
“It was one bang and essentially everyone from the other side of the arena where the bang was heard from suddenly came running towards us as they were trying to exit Trinity Way and that was blocked so everyone was just running to any exit they could find as quickly as they could.
“Everyone was in a huge state of panic, calling each other as some had gone to the toilet whilst this had gone off, so it was just extremely disturbing for everyone there.