At least 19 fans have died following an explosion at an Ariana Grande concert in Manchester.

Another 59 injured are receiving medical treatment in six hospitals across the city. "We are currently treating this as a terrorist incident," police have said in a statement, also telling people to stay away from the area.

@ManchesterArena So Scary! pic.twitter.com/4EoDNgR6bJ

— Chris Pawley (@ChrisPawley1) May 22, 2017

Video footage shows thousands of terrified people fleeing from the venue following the explosion, which seems to have taken place in the foyer. Emergency services are on the scene this morning and many major transport links will remain closed today. One witness told The Sun the arena was like "a war zone" in the minutes following the blast.

Three ambulances in five minutes have arrived at the specialist children's A&E at Manchester Infirmary. pic.twitter.com/coAG6sgyxW

— Ciaran Jenkins (@C4Ciaran) May 23, 2017

The tragedy is being described as the UK's worst terrorist attack since the London bombings almost 12 years ago and took place at the end of Ariana's gig - part of her Dangerous Woman tour at around 10.30pm. The venue at the time was packed to capacity - with all 21,000 tickets being been sold-out in advance.

#Manchester pic.twitter.com/LzMioNLp0J

— Ellie Cheetham? (@elliefreyax) May 23, 2017

The incident caused chaos and panic in the aftermath. Eyewitnesses told the BBC they subsequently saw nuts and bolts strewn around the venue and walking wounded were seen with deep leg wounds.

#Manchester Fan with injured legs at Ariana Grande gig explosion tonight pic.twitter.com/QLQOla4wix

— Alan Spence (@AlanSpenceEDL) May 22, 2017

"Someone came through the doors then bang," Gary Walker described to BBC Radio 5 Live. He had been waiting to pick his wife and daughter; his wife suffered a stomach wound and a broken leg.

Panicking at Victoria Station after @ArianaGrande concert. Hope everyone is all safe and well. pic.twitter.com/6Q5WNXFkFO

— Zach Bruce (@Zach_bruce) May 22, 2017

"That sound, the blood and those who where running around clueless with body parts and bits of skin missing will not be leaving my mind any time soon or the minds of those involved," Abby Mullen said in an emotional Facebook post. The audience was "full of beautiful young girls and boys and families," one woman who attended with her daughter stated in conversation with Sky News. Separated from their guardians in the panic, around 50 unaccompanied children have been taken to a nearby Holiday Inn.

OLIVIA CAMPBELL. IF YOU SEE HER PLEASE CONTACT ME. FAMILY ARE WORRIED SICK. WAS AT THE CONCERT TONIGHT. #MANCHESTER #MANCHESTERARENA pic.twitter.com/4jLcGlcDTA

— Aleshia Anne (@Hello_Leesha) May 23, 2017

Using the hashtag #MissingInManchester, social media is being flooded with images of several missing teenagers, posted by their desperately worried parents and siblings who have failed to make contact with them.

Please come home Lucy and let us know you're safe ? #MissingInManchester pic.twitter.com/sre856GWsU

— Mads?✨ (@_maddisonallen) May 23, 2017

The Canadian, Australian, and New Zealand leaders have all responded with messages of support; Theresa May has suspended her election campaign with her Home Secretary stating: "My thoughts are with all those affected by this barbaric act. "The full details of exactly what happened are still emerging, but I am proud of the police and first responders who reacted to this tragic incident so swiftly."

broken. from the bottom of my heart, i am so so sorry. i don't have words.

— Ariana Grande (@ArianaGrande) May 23, 2017

The Irish Ambassador to the UK, Daniel Mulhall, has stated: "Horrified by what's happened in Manchester. My thoughts & deepest sympathies are with all those affected by this terrible tragedy." Ms Grande herself tweeted in the aftermath, saying: "Broken. from the bottom of my heart, i am so so sorry. i don't have words." She was uninjured in the attack.

A post shared by Ariana Grande (@arianagrande) on Apr 3, 2017 at 1:44pm PDT

Nicki Minaj, Katy Perry, Jennifer Lopez, Bruno Mars, and Taylor Swift are among the stars also offering their condolences. A helpline has been set-up this morning and police have also said that a help-centre at the Etihad Stadium in Manchester will be up-and-running shortly.

An emergency number is available for those who are concerned about loved ones or anyone who may have been in the area - 0161 856 9400

— G M Police (@gmpolice) May 23, 2017