What we know about deadly bombing in Manchester

The deadly attack carried out by a suspected suicide bomber in Manchester, England, on Monday night left emergency personnel scrambling to secure the area, tend to the wounded and reunite lost children with their families.

Here's what we know about the incident:

-22 dead, 59 wounded

-Children among the dead

-Attack claimed by ISIS

-Salman Abedi: Sources familiar with the probe say U.K. authorities investigating the Manchester attack have reached a preliminary identification of the bomber as Abedi, a 22-year-old man

-U.K. Prime Minister Theresa May called the attack "sickening"

The blast

Greater Manchester Police said they were called to the concert venue just before 10:35 p.m. local time after emergency services "received more than 240 calls."

The explosion occurred near the arena's foyer after Grande exited the stage, according to witnesses, who said they heard a loud bang as they exited the concert.

The concert venue, which holds about 21,000 people, is one of Europe's largest indoor arenas, according to its website, and it is connected to the city's second-largest train station.

The wounded and the missing

Medical personnel are still tending to dozens of wounded, including children.

The wounded are being treated in several different area hospitals and some of them were battling life-threatening injuries, authorities said. Children were among the deceased, according to police.

Many people are still missing and an emergency hotline has been set up for people concerned for "loved ones who may not have returned home," police said. Social media giant Facebook activated its global "safety check" feature in the wake of the deadly attack.

The investigation

Police have said they believe the attack was carried out by "one man," who died at the scene after he detonated an "improvised explosive device." Police and intelligence officials immediately launched an investigation after Monday's incident.

On Tuesday, Manchester police announced the arrest of a 23-year-old suspect in connection with the attack.

So far, they have not said if there were any accomplices in planning or carrying out the attack or if any suspects have been linked to terrorist organizations.

The terror group ISIS claimed responsibility for the attack on Tuesday in an Arabic-language news release.

"The priority is to establish whether he was acting alone or as part of a network," Ian Hopkins, chief constable of Greater Manchester Police, said of the deceased attacker at a press conference early Tuesday.

"Our priority is to work with the national counter-terrorism policing network to establish more details about the individual who carried out this attack."

Police have not identified the nationality of the person behind the attack, but a former director of the security service M16 told BBC earlier that the bomber was likely already known to security services.

Prime Minister calls the attack 'sickening' after an emergency meeting on Tuesday

UK Prime Minister Theresa May called the suspected terrorist attack "sickening" and "appalling." May held an emergency COBRA meeting at 9 a.m. today. The group -- composed of government ministers, military and security chiefs -- typically meets after major incidents to plan the government's overall response.

The prime minister said the country' threat level remains at "severe," meaning the government considers another terror attack highly likely. Severe is level 4 out of 5, with critical being the highest.

May said the attacker deliberately targeted children and young people "who should have been enjoying one of the most memorable nights of their lives."

"We struggle to comprehend the warped and twisted mind that sees a room packed with young children not as a scene to cherished but as an opportunity for carnage," May said.

Ariana Grande's tour

It's not clear if Grande, who has two concerts scheduled in London later this week, will go on with her world tour as planned.

The pop star's Dangerous Woman tour was originally scheduled to end on September 21 in Hong Kong.

Grande was not hurt in the attack, but she tweeted last night that she was feeling "broken."

ABC News' Emily Shapiro contributed to this report.