The death toll from the Manchester bomb attack has risen to 22, with 59 injured, Greater Manchester Police chief constable Ian Hopkins said.
Police are currently treating the blast after the Ariane Grande concert as a suspected terrorist incident.
Greater Manchester Police said: “Just before 10.35pm on Monday May 22, police were called to reports of an explosion at Manchester Arena.
“This is currently being treated as a terrorist incident until police know otherwise.”
Witnesses reported hearing a “huge bang” at the venue shortly after US singer Ariana Grande’s gig finished on Monday evening.
Greater Manchester Police said there were a “number of confirmed fatalities and others injured” and emergency services are at the scene after reports of an explosion.
This morning, announcing that the death toll had risen, Greater Manchester Police chief constable Ian Hopkins said: “What I can confirm is that there are children among the deceased.
“This has been the most horrific incident we have had to face in Greater Manchester and one that we all hoped we would never see.
“Families and many young people were out to enjoy a concert at the Manchester Arena and have lost their lives.
“Our thoughts are with those 22 victims that we now know have died, the 59 people who have been injured and their loved ones.
“We continue to do all we can to support them.”
Mr Hopkins said a fast-moving investigation had established the attack was conducted by one man, although detectives are working to establish if he was acting alone or as part of a network.
“The attacker, I can confirm, died at the arena.
“We believe the attacker was carrying an improvised explosive device which he detonated, causing this atrocity.”
Andy Burnham, the Greater Manchester metro mayor, said the attack was an “evil act” that had caused anger, shock and hurt.
The former Labour MP said the city would do what it could to operate as usual.
He said: “It is hard to believe what has happened here in the last few hours, and to put into words the shock, anger, and hurt that we feel today.
“These were children, young people and their families that those responsible chose to terrorise and kill.
“This was an evil act.”
The area around the arena was swamped with police and emergency services and approach roads were closed.
Witnesses said they heard two loud bangs inside the arena coming from the area of the bars.
One fan at the concert with his sister described how the apparent explosion happened as fans were leaving the arena.
Majid Khan, 22, said: “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.”
Oliver Jones, 17, who attended with his 19-year-old sister, said: “The bang echoed around the foyer of the arena and people started to run.
“I seen people running and screaming towards one direction and then many were turning around to run back the other way.”
Another man who took his daughter to the gig said: “Ariana said: ‘Bye bye Manchester!’ The lights came on then there was two big noises and people started running and shouting.
“We got in a lift to go up to the next floor to the exits. When the doors opened I saw blood on the floor and two injured people. Blood all over their faces. A lot of people were in shock.”
Gary Walker, from Leeds, was with his wife in the foyer waiting to pick up his two daughters who were at the concert.
“I was waiting for the kids to come out. We heard the last song, and quite a few people were flooding out and then suddenly there was a massive flash and then a bang, smoke,” he told BBC Radio 5 Live.
“I felt a bit of pain in my foot and my leg. My wife said, ‘I need to lie down’. I lay her down, she’d got a stomach wound and possibly a broken leg.
“I was about three metres from the actual explosion. I am surprised I got away so lightly.”
Mr Walker said the explosion was by the door in the foyer, next to the merchandise, and that glass and metal nuts were left on the floor. He said he lay down next to his wife for up to an hour, until she was stretchered on a table to an ambulance.
His daughter Abigail, who was still in the auditorium with sister Sophie at the time of the explosion, said: “I had to make sure I had my sister. I grabbed hold of her and pulled hard. Everyone was running and crying.
“We were just trying to figure where everyone was. It was absolutely terrifying.”
Abigail and Sophie contacted their parents by mobile phone, a moment Mr Walker described as “fantastic news”.
Jade Baynes, 18, from Hull, was told to run from the area by armed police after leaving the concert arena.
She said she heard loud bangs and what sounded like gunshots just after the entertainment had finished.
She added: “There were just a loud bang and a flash and everyone tried to scramble out. An alarm came on telling everyone to stay calm but leave as quickly as possible.”
Jade and her friend Jasmine Mia, 21, also from Hull, said there appeared to be some sort of commotion in the first tier of the arena, with a number of stewards stood around the seats.
Greater Manchester Police carried out a “controlled explosion” in the Cathedral Gardens area near Manchester Arena around 1.30am.
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