Ariana Grande concert explosion: What we know

A police officer is pictured escorting people near the Manchester Arena in Manchester, England. At least 19 people died and 50 were injured after one or more explosions tore through the crowd at a concert by American pop star Ariana Grande late Monday night.

At least 22 people died and scores were injured after one or more explosions tore through the crowd at a concert by the American pop star Ariana Grande at the Manchester Arena in the United Kingdom on Monday.

Here's what we know so far:

What happened? 

The blast occurred just before 10:35 p.m. local time as the concert was wrapping up, according to Manchester police. The explosion, which apparently took place in, or just outside, the arena's main corridor, sent panicked fans running. Although some witnesses reported one explosion, a representative for Grande's label told Variety that there were two loud bangs.

People at the arena described a scene of chaos and terror.

Read more: 

At Manchester Arena, panic among the pink balloons

Was it a terror attack? 

Manchester police said this "is currently being treated as terrorist incident until police know otherwise."

British authorities were investigating the incident as a possible suicide bombing, a U.S. law enforcement official briefed on the matter told USA TODAY. The official, who is not authorized to comment publicly, said there had been no immediate claim of responsibility.

They think the attacker died at the scene.

A terrorism analyst from the Search International Terrorist Entities (SITE) Intelligence Group said that the Islamic State  has celebrated the attack on social media.

After the blast, police carried out a "precautionary controlled explosion" nearby on what turned out to be abandoned clothing, according to a tweet from the Greater Manchester police.

Police have asked the public to avoid the area around the arena.

Have the victims been identified? 

No, none of the identities of the people who were killed or wounded have been released. The wounded are being treated at six hospitals in the Manchester area.

People turned to social media in an effort to help those affected by the attack, offering everything from places to stay and free taxi rides to phone chargers under the Twitter hashtag #RoomForManchester.

Facebook activated its safety check for people in the area to let friends and loved ones know they are OK.

British police set up an emergency number for those seeking information about loved ones or with any information about the attack at (country code +44) 01618569400.

How did the international community react? 

World leaders condemned the attack after news of the incident spread. British Prime Minister Theresa May said her thoughts were with the victims and their families.

Canadian Prime Minister Justin Trudeau was "shocked" by the attack and asked for people to keep the victims and their families in mind:

Australian Prime Minister Malcolm Turnbull also reacted to the news with horror, saying the Manchester Arena attack was a  “brutal attack on young people everywhere," according to The Guardian, adding that: "This incident, this attack, is especially vile especially criminal, especially horrific because it appears to have been deliberately directed at teenagers. This is an attack on innocence."

New York Gov. Andrew Cuomo said he was "heartbroken" by the explosion in Manchester and said that state law enforcement would step up security and patrols.

Stars from Hollywood also reacted to the attack and took to social media to mourn. Cher, Demi Lovato, Ellen DeGeneres and Dwayne "The Rock" Johnson were among those who sent thoughts and prayers via social media.

'Ariana is OK' 

Grande was uninjured in the attack and is safe, the singer's record label publicist told the L.A. Times.

"Ariana is OK. We are further investigating what happened," said Joseph Carozza, Grande's publicist with Republic Records, according to The Times. 

At 10:51 p.m. ET Grande sent a tweet saying, "broken. from the bottom of my heart, i am so sorry. i don't have words."

Where is Manchester? 

Manchester is located about 200 miles northwest of London. It is the U.K.'s second-largest city with a population of more than 2.6 million people.

Read more: 

At least 19 dead in fatal blasts at Ariana Grande concert in U.K.

Stars react to deadly blast outside Ariana Grande concert