The Late Late Show host filmed this response to the attack.

Manchester Arena has a capacity of 21,000 and is the second biggest indoor arena in Europe.

As well as hosting some of the biggest musical performers in the world, it was used in 2002 for the Commonwealth Games.

Image source, Family photo

Thousands of people have turned to social media to help find missing relatives amid the chaos that followed the blast at Manchester Arena.

Olivia Campbell's face was one of many to appear on Twitter as her family appealed for information.

Olivia, 15, has been missing since the Ariane Grande concert, where the explosion happened at 22:35 BST on Monday.

Her mother Charlotte has appealed for people's help in finding her.

Read more here.

Gordon Corera
Security correspondent, BBC News

Image source, AFP/Getty Images

Police have said they believe the attack was carried out by a suicide bomber.

They have said the priority now is to understand if he acted alone or with help.

The UK threat level has been judged to be severe for nearly three years, which means an attack is considered highly likely.

But in recent months the tempo of counter-terrorist activity has been increasing, with on average an arrest every day.

In wake of the attack in Westminster by Khalid Masood in March, police and security officials have been warning that further attacks were almost inevitable.

But they also believed that those were almost more likely to be low tech, involving knives or vehicles.

The fact that the Manchester attack involved explosives will be of real concern.

It may not have been at the level of complexity seen in Paris in 2015, when multiple attackers sent from Syria used guns and suicide belts to target music venues, a sports stadium and restaurants.

But it will still have required a degree of planning to make what police say was an improvised explosive device.

Establishing who exactly was involved and if there was a wider network behind the suicide bomber will now be vital to establishing the level of danger that remains.

BBC News Channel

Cab drivers were offering to help concert-goers get home in the aftermath of the explosion, says Colin Paterson, BBC arts and entertainment correspondent.

"As I was there, taxis were asking people 'would you like a lift anywhere'," he told BBC News.

"There are stories of cab drivers coming from Liverpool offering people lifts."

He said many parents had left children at the concert and were waiting to collect them when the explosion happened.

In an Instagram post, the former Manchester United footballer said: "Heartbreaking news from Manchester. As a father & a human what has happened truly saddens me. My thoughts are with all of those that have been affected by this tragedy..."

BBC Monitoring
News from around the globe

Russian state media report that the country's president, Vladimir Putin, has sent a message of condolence to Theresa May.

"We strongly condemn this cynical, inhumane crime.

"We hope that its masterminds will not escape the punishment they deserve,” he said, according to government-funded news agency RIA Novosti.

President Putin also said Russia was ready to step up cooperation with the UK in combating terrorism.

Image source, AFP

BBC Radio 5 live

General election campaigning has been suspended by all the main political parties and the BBC's deputy political correspondent John Pienaar says the whole tone of the campaign will change when it resumes.

He told Radio 5 live: "It's been a very robust campaign so far, you would expect that to have escalated in the days that remain before polling day.

"Now I think this will change the tone of all that is said and done.

"The battle will continue, and it must and should continue, but this has now thrown the whole process into a very different light."

Brendan Cox, the husband of Labour MP Jo Cox, who was murdered in Birstall, West Yorkshire, on 16 June last year, tweeted his response to the attack.