MANCHESTER, England - Police arrested a man in a raid in south Manchester in connection to the bombing at an Ariana Grande concert in Manchester the previous night.

Police say the man is 23 years old but they haven't released any details about him. The bombing killed 22 and injured 59. Police said the bomber died in the attack.

CBS News confirmed Tuesday that the man who blew himself up at the concert in Manchester, England, was 23-year-old Salman Abedi, who was known to British authorities prior to the attack.

The first victim was identified Tuesday as 18-year-old high school student Georgina Callander. Her death was confirmed by her school administration.

The BBC identified another victim as Saffie Rose Roussos, 8.

The Islamic State of Iraq and Syria (ISIS) issued a claim of responsibility on Tuesday for the attack in a brief, generic statement that did not identify the bomber and appeared to get some of the facts of the attack wrong.

ISIS claimed a "caliphate soldier managed to place a number of devices among a gathering of crusaders in Manchester, and detonated them." Officials say there was only one explosion, and no other devices have been discovered at the arena.

The concert drew a sell-out crowd to Manchester Arena -- about 20,000 people -- and it was just ending. 

The last song was over and the young, happy crowd was beginning to file out of the arena. A dash-cam in one of the vehicles in the parking lot caught the massive blast.

There were seconds of silence, and then panic gripped the crowd. The bomber, a man who police say arrived alone, was not inside the arena when he detonated his explosives. He arrived on the local rail system and approached one of the main exits as the audience made their way out.

Kids and teenagers were everywhere, meeting parents and making their way out of the building.

Speaking Tuesday morning in London, British Prime Minister Theresa May called it a "callous terrorist attack; an attack that targeted some of the youngest people in our society with cold calculation."

She said the bombing stood out even among other attacks for the culprit's, "appalling, sickening callousness, deliberately targeting innocent children."

Witnesses painted a terrifying picture of a fun night out, turned into chaos and then tragedy.

"We were in the arena and we heard a bang and I just run for me life," concertgoer Charlotte Pinder said.

Another girl said everyone was "really confused. There was a big bang, smell of smoke, everyone was screaming and crying."

Chief Constable Ian Hopkins of the Manchester police called it "the most horrific incident we have ever faced here." He said there were children among the dead, and many more among the injured.

"We believe the attacker was wearing an improvised explosive device which he detonated causing this atrocity," Hopkins said.

There was security at the concert, but the bomber apparently didn't try to get into the venue -- his victims came to him. Prime Minister May said the attacker, who had been identified by police, deliberately chose "his time and place to cause maximum carnage" in the young crowd.

Tuesday morning, concertgoers were still wandering the streets of Manchester, many unable to make sense of what had happened. Police closed streets around the arena, and the Victoria train station, which is near the venue, also remained closed on Tuesday.

"You wouldn't think something like that would happen to you. And then when it happens to you, it's just so unreal," one young concertgoer told CBS News. "It really hits you… crying this morning, still trying to get in contact with everybody that we haven't, it's been awful."

A source also told CBS News one person was detained in a vehicle but it is not clear what, if any, involvement that potential suspect may have had in the incident.

A representative said Ariana Grande was not injured.

Late Tuesday, Grande shared a message on Twitter.

May confirmed that 22 people were killed and 59 others injured, not including the attacker, who also died. Many of the injured were being treated for life-threatening conditions, including children, she said.

The Associated Press contributed to this report.