A number of children are among those killed when an explosion erupted in a foyer at Manchester Arena on Monday evening.

The blast went off as fans of the US pop star were leaving, some to be picked up by their parents.

The terrorist attack has killed 22 people plus the attacker, and injured at least 59.

The NHS has said 12 children are among those injured, while a 23-year-old man has been arrested over the attack.

The force's chief Constable Ian Hopkins confirmed a number of children have died in the horror attack.

GMP have named the main suspect as Salman Ramadan Abedi, 22, from Manchester, as cops raided his home.

(Image: LONDON NEWS PICTURES/TWITTER) (Image: LONDON NEWS PICTURES)

Prime Minister Theresa May described the "appalling attack" of one of particular cowardice given the young victims.

Labour leader Jeremy Corbyn described it as "horrendous", saying communities will come together in solidarity and carry on.

She is due to chair an emergency COBRA meeting later today as the general election campaign was suspended.

Manchester City Council leader Sir Richard Leese said it was "hard to imagine" a worse night in the history of the city.

It is the worst terrorist attack on British soil since the 7/7 bombings in London in 2005.

Home Secretary Amber Rudd called the incident a "barbaric" attack on some of the "most vulnerable in our society".

She said the intention of the attack was to "sow fear" but added that it would not succeed.

The Queen has expressed her "deepest sympathy" to all those affected, adding that "the whole nation has been shocked by the death and injury".

Thousands gathered for a vigil in Manchester city centre in defiance of the terrorists.

(Image: TWITTER)

Little Saffie Rose Roussos, aged eight, 18-year-old Georgina Callander and John Atkinson, 26, are the first three victims to have been named.

Chief constable Hopkins said: "We are currently treating this as a terrorist incident.

"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."

Wythenshawe Hospital said it dealt with "mass casualties" and cleared other patients away from A&E to make way for those injured.

(Image: LONDON NEWS PICTURES)

(Image: DS)

Harrowing pictures from the scene show people rushing away from the concert at the packed arena and injured fans covered in blood.

Videos from inside the arena show frantic people running to try and escape the venue.

A package was later found in nearby Cathedral Gardens and a controlled explosion took place, although the item was not suspicious.

Victims in the arena have described being thrown by the blast that sent nuts and bolts flying through the air.

(Image: LONDON NEWS PICTURES)

A "fast-moving investigation" is under way, but cops have confirmed the attacker – said to be a lone male – died in the attack.

Police are now probing whether he "was acting alone or as part of a network".

Chief Constable Hopkins said: "We believe the attacker was carrying an improvised explosive device which he detonated, causing this atrocity."

Andy Burnham, the mayor of Manchester, paid tribute to emergency services and all Mancunians after the incident.

He said: "Even in the minutes after the attack, they opened their doors to strangers.

"We are hurt today but we are strong.

"That spirit of Manchester will prevail and hold us together."

(Image: LONDON NEWS PICTURES) (Image: LONDON NEWS PICTURES)

Witnesses described a "massive bang" as people were leaving the show – sparking mass panic and people rushing to escape the arena.

Helen Mongomery wrote: "Genuinely felt like an earhtquake. Hope everyone is ok."

Trains were halted at nearby Oxford Road station and passengers were evacuated.

Shocking videos from the scene show youngsters desperately fleeing the scene after the explosion rang out.

Footage has also emerged of people with horrific injuries caused by flying shrapnel.

(Image: LONDON NEWS PICTURES)

US President Donald Trump expressed his "deepest condolences" to the victims of the bombing calling attackers "evil losers".

Speaking in Bethlehem, he offered his prayers to the families of the 22 people who were killed in the blast last night.

Manchester United FC led the way in social media tributes to victims.

The hashtag ManchesterUnited has been going viral with people saying the words perfectly symbolise how the city is pulling together this morning.

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 while this had gone off, so it was just extremely disturbing for everyone there."