The man who carried out a suicide attack in Manchester was “likely” to have not acted alone, Home Secretary Amber Rudd says.
Salman Abedi killed 22 and injured 64 when he blew himself up at the Manchester Arena on Monday night – 20 people are in critical care.
The UK terror threat level is now up to its highest level of “critical”, meaning more attacks may be imminent.
It means military personnel will now be deployed to protect key sites.
Mrs Rudd said the attack was a “devastating occasion”.
“It was more sophisticated than some of the attacks we’ve seen before, and it seems likely – possible – that he wasn’t doing this on his own,” she added.
Who are the victims?
Five of the victims are known to be eight-year-old Saffie Roussos, Olivia Campbell, 15, Kelly Brewster, 32, John Atkinson, 28, and Georgina Callander – thought to be 18.
Two Polish people are also among those killed, according to a Polish government minister.
The injured are being treated at eight Greater Manchester hospitals. Of those, some have lost limbs.
The wounded include 12 children aged under 16.
Several people are still missing, including Eilidh MacLeod, 14, from Barra in the Outer Hebrides, Chloe Rutherford, 17, and Liam Curry, 19.
Eilidh’s friend, Laura MacIntyre, 15 – who was also reported as missing – was later identified as one of the seriously injured in a Manchester hospital.
Manchester metro mayor Andy Burnham told the BBC that the attack had been the city’s “darkest hour”.
A hotline has been set up for people concerned about loved ones – 0800 096 0095.
What does a ‘critical’ threat level mean?
Prime Minister Theresa May said soldiers would be placed in key public locations to support armed police in protecting the public. These include Buckingham Palace, Downing Street, embassies and the Palace of Westminster.
Military personnel may also be seen at other events over the coming weeks, such as concerts, Mrs May said, working under the command of police officers.
The prime minister said she did not want the public to feel “unduly alarmed” but said it was a “proportionate and sensible response”.
Mrs Rudd has said she “absolutely” expects the raising of the threat level to critical to be temporary.
She also said the bomber was known “up to a point” by the intelligence services.
Mrs Rudd also said there would be an “uplift” in Prevent, the government’s anti-radicalisation programme, after June. This had already been planned before Monday’s attack, she added.
It is understood that between 400 and 800 troops will be deployed in the first instance. Up to 3,800 are available.