Manchester attack: Theresa May raises terror threat rating to 'critical'
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The UK terror threat has been raised to critical in the wake of the Manchester suicide bombing attack amid fears attacker Salman Abedi did not act alone.
Monday night's attack at an Ariana Grande concert left 22 people dead and injured 64. Some 20 people are being treated for "horrific injuries" in critical care and 12 of those rushed to hospital were children.
Thousands of soldiers are set to bolster police forces after Theresa May raised the threat level to the highest possible rating, meaning another atrocity is expected imminently.
Five more suspects have been arrested in relation to the attack by Greater Manchester Police in new counter-terror raids.
Theresa May said a "wider group of individuals" could have been involved in the Manchester Arena blast rather than just suicide bomber Abedi.
In a sign of the increased threat, the military could be deployed to support armed police officers, Ms May added during a live televised statement from Downing Street.
Monday night's attack at a concert by US pop star Ariana Grande left 22 people dead, including an eight-year-old girl, and dozens injured.
Isis has claimed responsibility for the barbaric attack, which involved a home-made device packed with nuts and bolts which exploded in the venue's foyer as thousands of young people were leaving.
Abedi, believed to have been born in Manchester and of Libyan descent, has been named as the suicide bomber.
The 22-year-old studied business at Salford University but dropped out before completing his degree.
He is thought to have attended the Manchester Islamic Centre, also known as Didsbury Mosque, along with his parents and siblings.
Elsewhere in the city, the first arrest was made in connection with the inquiry when a 23-year-old man was detained near a Morrisons in Chorlton.
The terror threat level was increased after investigations revealed he may not have acted alone.
Ms May said Operation Temperer - allowing military personnel to take to the streets - is now in force.
Counter-terrorism agencies have 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:
Home Secretary Amber Rudd has said the UK terror threat level will remain at critical until the investigation into the Manchester Arena attack is no longer active.
Manchester bomber Salman Abedi was known to the intelligence services "up to a point", the Home Secretary added.
Ms Rudd disclosed that the intelligence services had been aware of British-born Abedi, who is reported to have recently returned to the UK from a visit to Libya.
She told Sky News: "We do know that he was known up to a point to the intelligence services".
Twenty people remain in "critical care" across Manchester with people suffering from "horrific injuries" including major organ damage and potential loss of limbs, Jon Rouse of the Greater Manchester Health and Social Care Partnership has said.
Mr Rouse confirmed some people have life-threatening injuries.
He told the BBC: "They've been the sort of traumatic injuries that you would expect in terms of the type of device used, the proximity to the people who were injured.
"We're dealing with injuries to major organs, we're dealing with loss of limbs potentially, we're dealing with embedded objects, all the horrific injuries that you would expect from the event that happened."
He said the victims were "receiving round-the-clock treatment from doctors and nurses".
Some 59 people were hurt in the attack and 12 of those rushed to hospital were children.
Home Secretary Amber Rudd refused to be drawn about the nature of the information held by the intelligence services about Abedi.
"I am sure that we will get more information about him over the next few days and the next few weeks," she said.
She said the threat level would remain at a heightened state while the investigation into the attack continued.
"It is an ongoing operation which means that the investigation is continuing to find leads," she said.
"So until we can be reassured that there is no continued activity around this operation, that is entirely safe around this operation, then it is right that we are at this heightened state of alert.
"It is operationally driven, it is intelligence-driven and we must make sure that we allow our counter-terrorist police, our police and our intelligence services to get on and do their job and this helps give them the space to do just that."
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