MANCHESTER, England -- Prime Minister Theresa May announced Tuesday night that the UK has raised its threat level to "critical" -- the highest level -- for the first time in a decade. The level suggests intelligence services believe an attack is "imminent."
And Britain is deploying soldiers to take over guard duties from police at key sites. It will be the first time in more than a decade that troops have patrolled civilian streets. And while the sight of the member of the armed forces outside concert venues and sporting events may be jarring, it is a temporary necessity, says May.
The presence of troops comes as the UK raised its threat level to "critical," its highest. Such a level indicates another attack could be "imminent."
"This morning, I said that the Joint Terrorism Analysis Centre -- the independent organization responsible for setting the threat level on the basis of the intelligence available -- was keeping the threat level under constant review.
It has now concluded, on the basis of today's investigations, that the threat level should be increased, for the time being, from severe to critical. This means that their assessment is not only that an attack remains highly likely, but that a further attack may be imminent.
The change in the threat level means that there will be additional resources and support made available to the police as they work to keep us all safe," UK Prime Minister Theresa May said in a statement.
"As a result of the JTAC's decision, the police have asked for authorization from the Secretary of State for Defence to deploy a number of armed military personnel in support of their armed officers. This request is part of a well-established plan, known as Operation Temperer, in which both the armed forces and the police officers involved are well trained and well prepared to work in this kind of environment. The Secretary of State for Defence has approved this request, and Operation Temperer is now in force.
This means that armed police officers responsible for duties such as guarding key sites will be replaced by members of the armed forces, which will allow the police to significantly increase the number of armed officers on patrol in key locations.
You might also see military personnel deployed at certain events, such as concerts and sports matches, helping the police to keep the public safe. In all circumstances, members of the armed forces who are deployed in this way will be under the command of police officers.
Precisely how the military and armed police officers will be deployed is an operational decision for police commanders, and Assistant Commissioner Mark Rowley of the Metropolitan Police will be making a statement giving further details at New Scotland Yard later this evening."
May says Salman Abadi, the suicide bomber who killed 22 people at a concert in Manchester, may have been part of a bigger network.
She said Abadi was born and raised in Britain.
The level previously stood at the second-highest rung of "severe" for several years.
May said critical status means armed soldiers may be deployed instead of police at public events such as sports matches.
Police identified 22-year-old Salman Abedi as the suspected suicide bomber who detonated bombs as throngs of teenagers poured out of an Ariana Grande concert in Manchester that killed 22 people.
The suspect carrying explosives acted as a lone attacker and died in the blast Monday night, which left the wounded and the dead scattered across the arena's bloodied entrance and sent screaming girls running for cover, according to police.
Greater Manchester Chief Constable Ian Hopkins named the suspect Tuesday but said that the man's identity had not been yet confirmed by a coroner.
The blast marked the deadliest terror attack on British soil since the 2005 London bombings. Hundreds of residents remembered the newest victims during a Tuesday evening vigil.
A powerful explosion shook part of the cavernous Manchester Arena late Monday as concertgoers streamed out following the American pop star's last song.
ISIS claimed responsibility for the attack but offered no evidence.
An 8-year-old girl and an 18-year-old woman have been named as the first victims of the attack, which has drawn condemnation and horror from around the world as a heinous assault targeting children.
- Ariana Grande suspends her world tour.
- Police have carried out two raids in Manchester.
- Queen Elizabeth II described bombing as "act of barbarity."
- 59 people injured, some in life-threatening situations.
- US President Donald Trump slams attackers as "losers."
- British Prime Minister says police have identified the suspect.
ISIS said on its Telegram channel Tuesday that a "soldier of the caliphate" was able to "plant explosive devices" at the arena, a US counter-terrorism source told CNN. ISIS routinely claims attacks it has no proven links with.
But authorities have discovered no evidence of a link between the attacker and an established terror group, a British counterterrorism official told CNN.
No determination has been on the sophistication of the explosive device or what chemicals were involved, the official said.
A US counterterrorism official said bombing "looks much like" an ISIS attack but that American intelligence officials were working with British counterparts to determine more.
On Tuesday evening, hundreds attended a vigil outside Manchester City Hall in honor of the victims.
"We will stand together to say that this city is greater than the force that aligns itself against it," David Walker, Bishop of Manchester, told the crowd. "We are sending a signal not just to Manchester, but across the world that you can not defeat us because love in the end is always stronger than hate."
Video from inside the arena showed girls screaming as they scrambled over chairs and railings to escape the 21,000-seat venue, while photographs showed bodies laying bloodied on the floor.
After an emergency Cabinet meeting, British Prime Minister Theresa May condemned the attack as "callous" and "cowardly."
"We struggle to comprehend the warped and twisted mind that sees a room packed with young children not a scene to cherish but as an opportunity for carnage," May said in London before leaving for Manchester.
Young victims named
Eight-year-old Saffie Rose Roussos from Leyland has been named as one of the fatalities, the Lancashire County Council confirmed.
Chris Upton, the head teacher at the Tarleton Community Primary School, described her as "simply a beautiful little girl" who was "quiet and unassuming with a creative flair."
Georgina Callander, 18, was also killed, according to her school, the Bishop Rawstorne Church of England Academy.
"All of our students will gather together today for a time of prayer and reflection and to give thanks for the life of Georgina," the school said.
At least 12 victims aged 16 or under were being treated at a children's hospital for serious injuries, some of them fighting for their lives, a Manchester health official said.
Grande, who had just finished the first of three scheduled UK performances, tweeted about her devastation several hours later: "broken. from the bottom of my heart, i am so so sorry. i don't have words."
The pop star has suspended her "Dangerous Woman" tour following the attack, a source with knowledge of the situation told CNN. Grande was scheduled to perform in London and across Europe through mid-June.
Queen Elizabeth II said Tuesday that "the whole nation has been shocked."
'Darkest of nights' in Manchester
Britain has been under a "severe" terror threat alert for three years and there has been an uptick in terror-related arrests in recent months.
Police have warned that another attack was likely after a man plowed his car into a crowd on London's Westminister Bridge in March and stabbed a policeman, in an attack that left six dead.
Monday's bombing has raised concerns that a more sophisticated network may exist in the country.
Greater Manchester Mayor Andy Burnham described the attack as "our darkest of nights."
"These were children, young people and their families that those responsible chose to terrorize and kill. This was an evil act," he said.
Around 400 police were deployed overnight following the attack, and on Tuesday, large groups of armed police were seen in several parts of the city. Security was boosted in London.
People began paying their respects to the victims on Tuesday afternoon. A family of four arrived at St. Ann's Square in the city center with a bouquet of flowers and balloons.
"I'm just feeling really down for all the families that lost their children and family members," said Michael Heveril.
"It's quite close to home -- I never thought anything like this would ever happen in Manchester."
The explosion rocked the arena at around 10:30 p.m. (5:30 p.m. ET). The sound of wailing sirens cut through the smoky aftermath.
Crying children and parents desperately tried to find each other as cell phone signals faltered, witnesses said.
Manchester resident Charlotte Campbell told CNN she waited for news on her 15-year-old daughter, Olivia. "We've tried everything we can. They're telling us to wait by the phones," she said.
Olivia had gone to the concert with a friend and neither have been in contact. Her father was looking for the girls.
"I want her home and I want her safe," Charlotte Campbell said. "I just want her to walk through the door."
Trump calls attackers 'losers'
US President Donald Trump slammed the attack, saying that terrorists were "losers."
"So many young beautiful innocent people living and enjoying their lives murdered by evil losers in life. I won't call them monsters because they would like that term. They would think that's a great name. I will call them from now on losers because that's what they are," he said. "This wicked ideology must be obliterated."
The US Department of Homeland Security said it was "closely monitoring" the situation.