Ariana Grande concert blast: 23-year-old arrested, ISIS claim responsibility for Manchester Arena attack

Police have made arrests in relation to the Manchester Arena bombing attack which killed 22 people, including children.

The arrests come as ISIS claimed responsibility for the suicide attack at the Ariana Grande concert.

In a statement published on its social media channels Islamic State declared that "one of the caliphate's soldiers placed bombs among the crowds," and threatened more attacks.

A 23-year-old man is among those arrested in the police investigation.

Authorities have confirmed a man involved in the attack died inside the arena wearing an explosive device.

Arrests were reported in south Manchester, Chorlton and Ashton. Police have not yet confirmed how many arrests have been made.

British PM Theresa May has said police know the identity of the attacker.

May called the attacks "appalling, sickening cowardice" and declared police would be given whatever resources needed to track down the accomplices.

“The terrorists will never win and our values, our country and our way of life will always prevail," she vowed.

Earlier, Greater Manchester Police chief constable Ian Hopkins said a single male attacker appeared to have detonated an improvised explosive device.

"The priority is to establish whether he was acting alone or as part of a network. The attacker, I can confirm, died at the arena," he said.

"We believe the attacker was carrying an improvised explosive device which he detonated causing this atrocity. We would ask people not to speculate on his details or share names.

"This is a complex and wide-ranging investigation. Our priority is to work with the National Counter Terrorist policing network and UK intelligence services to establish more details about the individual who carried out this attack."

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As Britain wakes up to the tragic news, police have revised the death toll to 22 after earlier reports of 19 fatalities.

More than 50 people were injured when an explosion tore through the Manchester Arena at about 10.30pm Monday, local time.

The American pop star's concert was largely been attended by children, teenagers and young people.

Earlier, Leeds father Gary Walker told BBC radio he believed that the blast came from an explosive device.

He said he had been waiting in the foyer with his wife for their child when the explosion occurred.

He said he was standing about three metres from the epicentre and said he saw metal nuts he believed were part of an explosive device.

The injured are being treated at eight hospitals in the area. Police said about 240 emergency calls were logged in the minutes following the explosion.

Hundreds of armed police have been deployed onto the streets of Manchester after scores of children spent the night huddled in hotels and motels turned makeshift shelters.

Meanwhile, their panicked parents turned to social media in desperate efforts to find their loved ones.

The British Prime Minister and Australia's Prime Minister both condemned the attack, which Malcolm Turnbull called a "vile attack on the innocent".