Fatalities after 'explosion' at Manchester pop concert
The Northwest Counterterrorist Unit have said they are responding to a "possible terror incident" at the Manchester Arena.
Greater Manchester Police found a second suspect device and carried out a controlled explosion.
An explosion took place in the foyer of the arena at 22:30 GMT, police said. Manchester Arena said the incident took place outside the arena, where crowds were likely gathered after leaving the concert.
Greater Manchester Police tweeted that a full report is due "as soon as available".
Videos showed crowds fleeing the venue following the sound of an explosion.
After reports of a loud bang being heard near the end of the concert, people began to rush for the exits.
The Greater Manchester Police sent a tweet out warning locals to avoid the area.
"Police responded to reports of an incident at Manchester Arena. Please stay away from the area".
One eyewitness said that she heard a "loud bang" from her home, which woke her up.
Another eyewitness told the BBC that he was "blown off his feet" and the explosion came from the box office on the way into the doors of the arena.
Some had initially speculated that the noise came from balloons popping.
Others have said among those injured were covered in blood and that the streets surrounding were "flashing with blue lights and helecopters".
"Everyone was screaming and running, there were coats and people's phones on the floor. People just dropped everything," Robert Tempkin, 22, from Middlesbrough, told the BBC.
— G M Police (@gmpolice) May 23, 2017
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Train services to and from Manchester Victoria Station - located under the Arena - had been cancelled.
Pop-star Ariana Grande has responded, expressing her heartbreak at the situation.
"Broken. from the bottom of my heart, I am so so sorry. I don't have words," she said on her Twitter page.