Nineteen people have been killed and at least 50 people left injured following an explosion at Manchester Arena which is being treated as a terrorist incident by a suspected suicide bomber.
Footage shows thousands of panicked young people fleeing the arena after an explosion went off at around 10.40pm.
Eyewitnesses said the explosion sounds were heard outside the auditorium after the artist had finished her show and left the stage, with people claiming on social media they believed the bangs were a bomb.
A concert-goer named Josh told the BBC there was huge panic and confusion as people tried to flee the arena, 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 loud bangs resonated as fans were leaving the venue, 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 people 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.”
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."
He said there were "a good 20 to 30 people lying injured" close to the box office, on the way into the arena.
"Whoever's done it has done it on a kids' concert," he said, adding that the whole building had shook from the force of the explosion.
Another eyewitness said he was thrown "30 feet in the air" by the force of the explosion.
A witness named Karen who was at the concert with her husband and children described the pandemonium as thousands tried to escape the venue after the explosion sound was heard.
"It was just chaos... nobody was organising anybody to do anything."
She added that she saw a woman in a wheelchair being pushed over as people desperately tried to get out after someone had shouted that there had been a bomb.
NBC reported that a representative of the 23-year-old pop star said: "Ariana is okay. We are further investigating what happened."
One of the singer's support acts, American singer and rapper BIA, also known as Bianca Landrau, said on Twitter: "We are okay" and thanked her fans for their concern.
Liverpool City Metro Mayor Steve Rotheham said on Twitter that his two daughters had been at the concert but had made it home safely. He thanked the taxi driver who had assisted them, and offered his sympathies to other parents waiting anxiously for news of their children.
Emergency services are said to be in attendance at the venue close to Manchester Victoria station with police helicopters reported to be circling overhead.
Police have warned people to stay away from the arena while investigations take place and put out a a statement confimring the number of fatalities shortly after 1am.
Police confirmed a bomb disposal squad carried out a controlled explosion of a suspect device around 1am.
Condolences began flooding in as the full horror of the incident became clear.
Manchester City football club tweeted: "It's with great sadness we hear of the terrible events at the Arena. Our hearts go out to all affected and to our city's emergency services.''
Offers of help and shelter for people stranded in the city began flooding in on social media.
