At least 22 people were killed and more than 59 others were injured Monday night in an explosion at an Ariana Grande concert in the British city of Manchester that police said was caused by a bomber carrying an improvised explosive device.
The explosion happened near an entrance to the 21,000-seat arena just minutes after Grande's concert ended with the song "Dangerous Woman" and the singer left the stage, witnesses said.
Many of the concert's attendees were girls and young women, some clutching pink balloons, who had come to see one of the world's biggest pop stars. After the explosion, many children were either separated from their parents or came unaccompanied and didn't know where to go.
British investigators said the attack appeared to be the work of a suicide bomber who entered a crowded area outside the performance space where attendees were streaming out of the concert.
"We are working to establish the full details of what is being treated by the police as an appalling terrorist attack," British Prime Minister Theresa May said in a statement. "All our thoughts are with the victims and the families of those who have been affected."
May, who suspended her campaign for parliamentary elections set for June 8, was expected to chair a meeting of the government's inter-agency emergency committee on Tuesday morning.
Police have focused their investigation on one man whose actions suggest he was the attacker, according to a law enforcement official not authorized to discuss the investigation.
The suspect was captured on a video security system, the source said. Police are working to confirm the identity of the man and are seeking any of his associates.
Police early Tuesday said the suspected bomber, who has not been identified, had died at the scene.
"The attacker, I can confirm, died at the arena. We believe the attacker was carrying an improvised explosive device which he detonated, causing this atrocity," Chief Constable Ian Hopkins said in a statement.
The explosion appeared to occur near an entrance where fans typically pick up tickets, an area where many parents were waiting after the concert to collect their children. Cordons blocked off the entire area as a swarm of police cars and ambulances moved in and began evacuating bleeding concert patrons.
The North West Ambulance Service reported taking 59 patients to hospitals and treating more at the scene.
Grande was not injured. "Ariana is OK. We are further investigating what happened," said Joseph Carozza, the artist's publicist with Republic Records, a division of Universal Music group.
Later, Grande tweeted. "Broken," she wrote. "From the bottom of my heart, I am so sorry. I don't have words."
Her manager, Scooter Braun, followed up with a statement. "Words cannot express our sorrow for the victims and families harmed in this senseless attack. We mourn the lives of children and loved ones taken by this cowardly act," it said in part.
Police raised the death toll to 22 at a news conference Tuesday morning.
Authorities disclosed few details of the preliminary investigation into the incident they said was first reported at 10:33 p.m.
"We are currently treating this as a terrorist incident until we have further information," Hopkins told reporters. "This is clearly a very concerning time for everyone. We are doing all that we can."
Fans from around northern England had flocked to the arena near the heart of Manchester, about 165 miles north of London, to see Grande's "Dangerous Woman" tour. The show ended around 10:30 p.m.
Concertgoer Danny Keeling, 22, said he had left shortly before the end of the concert to avoid the crowds. "Everyone was completely happy," he recalled.
Then, at least one explosion ripped through an area near the arena's box office, which was crowded with fans leaving the show.
"And the next thing it was complete chaos," Keeling said. "We saw a guy being treated by paramedics, who had holes in his back from where the shrapnel had hit him, and there were kids with blood on them."
Another attendee, Charlotte, 18, from Manchester, had just left the arena when she heard the blast from the box office area. An eerie silence fell over the attendees outside, she said.
"Everyone stopped and all talking stopped," she wrote in a direct message on Twitter. Then she saw people running out of the exits. "Everyone was running and screaming. And people was screaming evacuate."
Lauren Sanders, 15, was near the stage when she heard an explosion that seemed to come from near the entrance of the theater, where the audience had streamed toward the exits, perhaps two minutes after Grande left the stage.
"Then everyone who was leaving started screaming and running the other way to another exit," Sanders wrote in a direct message on Twitter. A huge Grande fan, she had come to the concert with her mother. She said there were no metal detectors and that security did not carefully check her mother's bag.
After the explosion, "I grabbed my mum's hand and started running, following a lot of others towards an exit," Sanders said. Outside, police were everywhere, trying to clear the area, she said.
Alex Clare, 27, was walking his dog about half a mile away from the concert arena when he heard the explosion. As he approached the area he said he was taken aback by the scene.
"There were swarms of police cars and ambulances and I saw people with blood on their face," Clare said. "A gentleman approached us with his daughter and started crying and said he had just seen people blown to bits."
Gary Walker, who is from Leeds, was waiting with his wife for their two daughters to come out of the concert when the explosion happened just yards away. "We heard the last song go, and then suddenly there was a massive flash and then a bang and smoke," he told BBC 5 live. He felt pain in his foot and leg.
"I turned around to my wife who was standing at the side of me and she said, 'I need to lay down.'" He said she had a stomach wound and possibly a broken leg. "I've got a bit of a hole in my foot where I've got a bit of shrapnel," he said. "I was surprised I got away so lightly."
Matt Ledger, 19, was with two of his friends at the concert when he heard one of the explosions. "Everyone starting sprinting and grabbing each other," Ledger said in a phone interview. "When I got outside I saw a few people laying on the grass and their heads were bleeding."
Ledger, who lives two hours outside of Manchester and came in for the concert, said he ran 10 minutes away to a bar, where he took shelter for two hours.
As in previous incidents in Europe, people took to social media to offer rides, rooms for the night and tea to those in need using the hashtag #RoomForManchester. Others used the hashtag to send out anguished pleas for information about the missing. "My friend is missing in the concert haven't heard of him please contact me #Manchester #RoomForManchester worried and sick now," read one tweet.
"My heart goes out to families who have lost loved ones, my admiration to our brave emergency services," Andy Burnham, the mayor of Greater Manchester, wrote on Twitter. "A terrible night for our great city."
Concertgoers said the number of unaccompanied youngsters in the crowd contributed to the panic when the explosion happened. "I was trying to offer my support to a number of girls who were there on their own who were hysterical," the mother of a 13-year-old, who gave her name as Anne-Marie, told BBC 5 live. "They were around my daughter's age if not younger."
Some survivors fled to the nearby Steven Charles Snooker Center, where a bartender reported hearing a sound from the arena like "thunder."
"We've got four girls here — trying to get them sorted to get picked up. There was a gentleman on the floor with his leg all bleeding and a woman with blood down one side of her face," the bartender, who gave his name as Tyler, told the Press Assn. "One girl had a panic attack and another had streaming tears, a woman had a heart attack just outside."
After the explosion, police carried out a controlled explosion of a suspicious item near the arena but later said it was just clothing.
Some concertgoers began raising questions about security at the venue. Keeling said security personnel were checking bags, but not patting anyone down. "I told my friend you could have anything on you, and you can bring in anything," he said.
The U.S. Department of Homeland Security said in a statement that it was monitoring the situation in Britain and working with international law enforcement partners. It also cautioned Americans around Manchester to "maintain security awareness."
"At this time, we have no information to indicate a specific credible threat involving music venues in the United States," the department's statement said. "However, the public may experience increased security in and around public places and events as officials take additional precautions."
Grande was scheduled for additional performances on her Dangerous Woman Tour on May 25 and 26 at London's O2 Arena, according to the website of the tour promoter, Live Nation UK. Tour officials have not yet said whether those events will be canceled.
"We are deeply saddened by this senseless tragedy and our hearts and thoughts are with those impacted by this devastating incident," a Live Nation spokeswoman said.
Times staff writers Randy Lewis, Todd Martens and Alexandra Zavis contributed to this report. Boyle reported from London and Pearce, Etehad and Winton reported from Los Angeles.
12:05 a.m. May 23: The article was updated with additional details about the suspected bomber.
11:10 p.m.: The article was updated with a new death toll.
9:25 p.m.: The article was updated with a statement from Grande's manager.
7:55 p.m.: The article was updated with a tweet from Ariana Grande and a statement from the U.S. Department of Homeland Security.
7:30 p.m.: The article was updated with additional information from the prime minister's office.
7:05 p.m.: The article was updated with a statement from the prime minister.
6:15 p.m.: The article was updated with additional witness accounts.
5:50 p.m.: The story was updated with information that law enforcement officials are investigating the incident as a possible suicide bombing.
5:25 p.m.: The story was updated with official casualty figures, new details on the explosion and witness accounts.