A heartbreaking video shows thousands of youngsters singing 'One Last Time' with Ariana Grande just moments before the blast at Manchester Arena. Facebook / Anushka Moore
KEY POINTS:
22 killed, at least 59 injured after blasts at end of Ariana Grande teen concert in Manchester
Suicide bomber identified as Salman Abedi
British PM Theresa May raises country's terror threat to critical, says another attack may be "imminent"
Soldiers deployed on streets
Attack conducted by one man, whowas carrying a device that he detonated
Islamic State has reportedly claimed responsibility for the attackundefinedMost victims believed to be teens; video shows panicked young fans fleeing venue in tears
First victim named locally as 18-year-old Georgina Callander
Second victim named as 8-year-old Saffie Rose Roussos
Witnesses describe "carnage everywhere" at conclusion of concert
Ariana Grande tweets "from the bottom of my heart, I am so so sorry. I don't have words"
Up to 5000 soldiers will be deployed on the streets amid fears that the Manchester suicide bomber had accomplices preparing further attacks, Theresa May has announced.
For the first time in 10 years, the Prime Minister raised the terror threat to the highest possible level, from severe to critical, meaning an attack is "expected imminently".
Investigators fear that the British-born bomber Salman Abedi, a 22-year-old of Libyan descent, was part of a wider network of Isis-inspired terrorists, including a bomb-maker, who may still be at large.
Special Forces were deployed to Manchester to help hunt for accomplices of Abedi, who killed 22 concert-goers in Britain's worst terrorist atrocity for 12 years.
Outlining the increased risk, May said: "It is a possibility we cannot ignore that there is a wider group of individuals linked to this attack."
May also announced that troops would replace police officers at major events including sports fixtures and concerts.
It will be the first time since 2003, when the Government reacted to a plot to bring down an airliner, that troops have been deployed on the streets.
People running through Manchester Victoria station after an explosion at Manchester Arena. Photo / AP
With the FA Cup final this weekend, May acted on the advice of the Joint Terrorism Analysis Centre after chairing two meetings of the Cobra emergency committee.
Security will also be stepped up at major public events and terrorist targets such as railway stations and airports.
It is the first time Britain has been on maximum terrorist alert since 2007, when a blazing car loaded with gas canisters was driven into Glasgow Airport.
A 23-year-old man was arrested in Manchester in connection with the attack and was being questioned.
Fans leave the Park Inn hotel in central Manchester. Photo / AP
Intelligence experts believe the device detonated at an Ariana Grande concert at the Manchester Arena on Monday night was so sophisticated that Abedi must have either been given specialist training abroad or used a bomb made by a technician who has not yet been captured.
It emerged that Abedi had travelled to Libya, raising fears he had been trained there and posing questions for the security services on whether he should have been tracked.
Police confirmed that an 8-year-old girl was among those killed.
Grande has a huge following among young girls and other children are understood to be among the dead. Twelve children were among 59 taken to hospital after the atrocity, for which Isis has claimed responsibility.
May described the bombing as "one of the worst terrorist incidents we have ever experienced in the United Kingdom" and said it "stands out for its appalling, sickening cowardice - deliberately targeting innocent, defenceless children and young people who should have been enjoying one of the most memorable nights of their lives".
Police escort members of the public from the Manchester Arena. Photo / AP
Sources confirmed to the Daily Telegraph that Special Forces soldiers had been sent to Manchester to support the police in the hunt for other potential bombers.
Military bomb disposal experts were already involved on Tuesday when police stormed the house in the Fallowfield area of Manchester where Abedi is believed to have lived with relations.
Current threat level for international terrorism: Severe
• Low: Means an attack is unlikely • Moderate: Means an attack is possible, but not likely • Substantial: Means an attack is a strong possibility • Severe: Means an attack is highly likely • Critical: Means an attack is expected imminently
