Salman Abedi, 22, ID'd as suicide bomber in Manchester attack

British police on Tuesday identified the suicide bomber who killed 22 people, including children, in an attack on a crowded arena in Manchester, and said they were trying to establish whether he had acted alone or with help from others.

The man suspected of carrying out Britain's deadliest bombing in nearly 12 years was identified as Salman Abedi, 22, but police declined to give further details about him. U.S. security sources, citing British intelligence officials, said he was born in Manchester in 1994 to parents of Libyan origin.

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He is believed to have travelled by train from London before the attack, they said. "Our priority, along with the police counter-terrorism network and our security partners, is to continue to establish whether he was acting alone or working as part of a wider network," Greater Manchester Police Chief Const. Ian Hopkins said.

British Home Secretary Amber Rudd said Wednesday that Abedi was known "up to a point" to the British intelligence
services and police.

She said the investigation is continuing and declined to provide further details.

France says Abedi had been to Syria

Meanwhile, France's interior minister said Abedi is believed to have travelled to Syria and had "proven" links with ISIS.

Gerard Collomb said on BFM television Wednesday that British and French intelligence have information that Abedi had been to Syria. He did not provide details, and said it is unclear whether Abedi was part of a larger network of attackers.

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The attacker set off an improvised bomb as crowds streamed out of the Manchester Arena after a pop concert by Ariana Grande, a U.S. singer who is especially popular with teenage girls.  

On Tuesday evening, thousands of people attended a vigil for the dead in central Manchester.

'This attack stands out for its appalling sickening cowardice..."- Theresa May

"All acts of terrorism are cowardly," Prime Minister Theresa May said outside her Downing Street office after a meeting with security and intelligence chiefs. "But this attack 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."

ISIS, now being driven from territories in Syria and Iraq by Western-backed armed forces, claimed responsibility for what it called a revenge attack against "Crusaders," but there appeared to be contradictions in its account of the operation. Police raided houses in Manchester and arrested a 23-year-old man.

Britain has increased its  security threat level to "critical" from "severe" following the attack, the prime minister said Tuesday.

May said members of the armed forces would boost security at key sites and military personnel might be deployed  at public events such as concerts and sports events.

The prime minister said the independent body which sets the threat level has "concluded on the basis of today's investigations that the threat level should be increased for the time being from severe to critical," she said in a televised statement following a meeting of the government's crisis response committee.

"This means that their assessment is not only that an attack remains highly likely but that a further attack may be imminent."

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Metropolitan Police Assistant Commissioner Mark Rowley, head of national counter-terrorism policing, said in a statement Tuesday night that the investigation is underway.

"It is still not possible to be certain if there was a wider group involved in the attack; 24 hours in we have a number of investigative leads that we are pursuing to manage the ongoing threat," Rowley said.

He noted that any military deployed alongside police would be "part of an agreed and well-rehearsed plan and military personnel will remain under the command and control of the police service."

Frantic searches

Witnesses related the horror of the blast, which unleashed a stampede just as the concert ended at Europe's largest indoor arena, full to its capacity of 21,000.

"We ran and people were screaming around us and pushing on the stairs to go outside and people were falling down, girls were crying, and we saw these women being treated by paramedics having open wounds on their legs ... it was just chaos," said Sebastian Diaz, 19. "It was literally just a minute after it ended, the lights came on and the bomb went off."

The attack was the deadliest in the U.K. since four British Muslims killed 52 people in suicide bombings on London's transport system in 2005. But it will have reverberations far beyond British shores. Attacks in cities including Paris, Nice, Brussels, St. Petersburg, Berlin and London have shocked Europeans already anxious over security challenges from mass immigration and pockets of domestic Islamist radicalism.

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ISIS has repeatedly called for attacks as retaliation for Western involvement in the conflicts in Syria and Iraq.

While claiming responsibility on its Telegram account, the group appeared to contradict the police description of a suicide bomber. It suggested explosive devices were placed "in the midst of the gatherings of the Crusaders."

"What comes next will be more severe on the worshippers of the cross," the Telegram posting said. It did not name the bomber, as it usually does in attacks it has ordered, and appeared also to contradict a posting on another ISIS account, Amaq, which spoke of "a group of attackers." That reference, however, was later removed.

'Wanton and depraved'

May said security services were working to see if a wider group was involved in the attack, which came less than three weeks before a national election. Campaigning was suspended as a mark of respect.

May spoke to U.S. President Donald Trump, French President Emmanuel Macron and several other foreign leaders on Tuesday about the attack, her spokesperson said. She also visited the police headquarters and a children's hospital in Manchester.

The White House said Trump had agreed with May during their telephone conversation that the attack was "particularly wanton and depraved."

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The UN Security Council condemned "the barbaric and cowardly terrorist attack" and expressed solidarity with Britain in the fight against terrorism. Queen Elizabeth held a minute's silence at a garden party at Buckingham Palace in London.

British police do not routinely carry firearms, but London police said extra armed officers would be deployed at this weekend's soccer cup final at Wembley and rugby at Twickenham. Security will be reviewed for smaller events.

In March, a British-born convert to Islam drove a car into pedestrians on London's Westminster Bridge, killing four people before stabbing to death a police officer who was on the grounds of Parliament. The man was shot dead at the scene.

In 2015, Pakistani student Abid Naseer was convicted in a U.S. court of conspiring with al-Qaeda to blow up the Arndale shopping centre in the centre of Manchester in April 2009.