The suicide bomber who brought carnage to the Manchester Arena has been named as Salman Abedi.
Police confirmed his name after armed officers carried out a dramatic raid on the redbrick semi in south Manchester where the 22-year-old, believed to have been of Libyan decent, was registered as living.
Greater Manchester Chief Constable Ian Hopkins said detectives were working to establish whether Abedi, whose attack left 22 people dead, including an eight-year-old girl, was working alone.
He said: “I can confirm that the man suspected of carrying out last night’s atrocity has been named as 22-year-old Salman Abedi.
“However, he has not yet been formally identified and I wouldn’t wish, therefore, to comment further.
“The priority remains to establish whether he was acting alone or as part of a network.”
Abedi had been a student at Salford University.
Residents of Elsmore Road in Fallowfield where he lived described being ordered to remain indoors as more than 20 officers, all armed, swooped on the house, carrying out a controlled explosion on the front door.
Elsewhere in south Manchester, the first arrest was made in connection with the inquiry when a 23-year-old man was detained near a Morrisons in Chorlton.
The Islamic State terror group claimed responsibility for the barbaric attack involving a homemade device packed with nuts and bolts which exploded in the foyer of the Manchester Arena as thousands of young people were leaving the concert by US pop star Ariana Grande.
As counter-terrorism agencies mounted a massive inquiry into the outrage - the worst terrorist attack since 52 innocent people were killed in the July 7 bombings in London in 2005:
• The first victims were confirmed as eight-year-old Saffie Rose Roussos from Leyland and teenager Georgina Callander from nearby Chorley. Saffie was at the concert with her mother Lisa and Saffie’s sister, Ashlee Bromwich, who is in her 20s
Words cannot express our sorrow for the victims and families harmed in this senseless attackGrande’s management team
• Many of the 59 people hurt in the attack were treated for life-threatening injuries. Twelve of those rushed to hospital were children.
• Andrew Parker, the Director General of MI5, condemned the “disgusting attack” and declared that the agency remains “relentlessly focused” on tackling the “scourge of terrorism”.
Thousands of people gathered in the centre of the city on Tuesday evening in an act of solidarity, with crowds spilling from Albert Square on to nearby roads, standing together. Crowds also gathered in Glasgow.
Mrs May said the perpetrator had chosen the time and place of his attack deliberately to cause “maximum carnage and to kill and injure indiscriminately”.
After flying to Manchester to speak to police chiefs and medics treating some of the child victims, the Prime Minister said: “It is an absolutely barbaric attack that has taken place, to cut off young lives in this way and it is absolutely devastating, and our thoughts and prayers must be with their families and friends at this horrendous tragedy that has taken place.
“I’m very clear that the police and the security services have the resources to ensure that they continue their investigation.”
She added: “I’ve just been hearing of police officers who were off duty turning up, wanting to ensure that they could contribute, that they could help.
“So many people have helped. That’s the great spirit of Manchester, the spirit of Britain, and one thing I’m clear is that the terrorists will not prevail.”
She later signed a book of condolence at Manchester Town Hall, writing: “Here in this great city a callous and cowardly act was met by the inspirational bravery of our emergency services and the unbreakable spirit of the people of Manchester.
“As we remember those who died, their loved ones and those who were injured, we will celebrate those who helped, safe in the knowledge that terrorism never wins and our values, our country and our way of life will prevail.”
The death of Saffie Rose Roussos, the youngest known victim of the attack, was described by her headteacher as “heartbreaking”.
Chris Upton, of Tarleton Community Primary School, said: “Saffie was simply a beautiful little girl in every aspect of the word.”
Another victim was named by her college as Georgina Callander, who was studying health and social care at Runshaw College in Leyland, Lancashire.
Tributes were also paid to 26-year-old John Atkinson from Bury, who was named by friends on Facebook as an apparent victim.
Meanwhile, fears were growing for Chloe Rutherford, 17, and Liam Curry, 19, a couple from South Shields, 15-year-old Olivia Campbell from Manchester and Eilidh MacLeod, from Barra in Scotland, Kelly Brewster from Sheffield, and Martyn Hett and Wendy Fawell.
All were believed to have been at the concert and had not been traced since the attack.
Scottish teenager Laura MacIntyre, who was reported missing, is being treated in hospital for serious injuries, family friend and SNP candidate Angus MacNeil has said.
The bomb was designed to cause maximum carnage, sending metal fragments flying through the the foyer.
A rough sleeper tearfully described the scene as he rushed to help.
Chris Parker, 33, who was in the foyer, where he regularly goes to beg for money as concert crowds head home, recalled: “Everyone was piling out, all happy and everything else.
“As people were coming out of the glass doors I heard a bang and within a split second I saw a white flash, then smoke and then I heard screaming.
“It knocked me to the floor and then I got up and instead of running away my gut instinct was to run back and try and help.
“There was people lying on the floor everywhere.
“I saw a little girl ... she had no legs. I wrapped her in one of the merchandise T-shirts and I said ‘where is your mum and daddy?’
“She said ‘my dad is at work, my mum is up there’.”
He said he thought the child’s mother had died from her injuries.
Mr Parker, who has slept rough in the city for about a year, said he also tended to a woman aged in her 60s who was badly hurt from the bombing with serious leg and head injuries.
He said: “She passed away in my arms. She was in her 60s and said she had been with her family.
“I haven’t stopped crying.
“The most shocking part of it is that it was a kids’ concert.
“There were nuts and bolts all over the floor. People had holes in their back.”