An explosion that appeared to be a suicide bombing killed at least 22 people on Monday night and wounded 59 others at an Ariana Grande concert filled with adoring adolescent fans, in what the police were treating as a terrorist attack.
Panic and mayhem seized the crowd at the Manchester Arena as the blast reverberated through the building, just as the show was ending and pink balloons were dropping from the rafters in a signature flourish by Ms. Grande, a 23-year-old American pop star on an international tour.
Traumatized concertgoers, including children separated from parents, screamed and fled in what appeared to be the deadliest episode of terrorism in Britain since the 2005 London transit bombings.
Speaking to reporters early Tuesday, Manchester’s chief constable, Ian Hopkins, said the police learned of the explosion around 10:33 p.m. Children were among those killed, he added, and the wounded were taken to eight hospitals.
Chief Constable Hopkins said that a man detonated “an improvised explosive device” and was killed in the blast. He said the police believed the man acted alone in the attack but were trying to determine whether he was part of a wider network. Other officials said the police were investigating reports that the device used nuts and bolts as shrapnel.
The scene in downtown Manchester immediately evoked the terrorist attacks in Paris in November 2015, which included a deadly assault inside the Bataclan concert hall, where the Eagles of Death Metal had been playing. But unlike the Bataclan show, the Manchester concert was filled with young teenagers.“This is currently being treated as a terrorist incident until the police know otherwise,” the Manchester police said in a Twitter post.
Prime Minister Theresa May said her thoughts were with the victims and their families in “what is being treated by the police as an appalling terrorist attack.” She was scheduled to lead a meeting of the government’s crisis response committee on Tuesday morning.
At least one explosion went off in the foyer of the arena, according to the British Transport Police, the force that protects the Manchester Victoria train station next to the arena. The terminal was evacuated.
Early Tuesday morning, Sky News reported that a bomb disposal team had arrived on the scene as part of the investigation and that the security cordon around the arena had been widened.
Gary Walker, who was at the show with his wife and two daughters, said he “heard a massive bang and saw a flash” just as the concert concluded. He turned and realized that his wife had been hurt. Mr. Walker, who is from the northern city of Leeds, said she had a stomach wound and possibly a broken leg. He said he lay down on the floor beside her and saw “metal nuts on the floor.”
Ms. Walker was taken to a hospital, Mr. Walker said while standing with his daughters at Deansgate, the main shopping street in Manchester.
Another concertgoer, Sasina Akhtar, told The Manchester Evening News that there had been an explosion at the back of the arena after the last song. “We saw young girls with blood on them,” she said. “Everyone was screaming, and people were running.”
Ms. Grande, a singer with a big voice who started her career as a star on a Nickelodeon TV series, is on an international tour supporting her 2016 album, “Dangerous Woman.” Two additional acts, Victoria Monét and Bia, performed as openers on Monday. The tour was scheduled to continue on Thursday at the O2 Arena in London.
Ms. Grande was not hurt. TMZ, the entertainment news website, reported that she was “in hysterics” over the deadly blast
Her manager, Scooter Braun, said on Twitter, “We mourn the lives of children and loved ones taken by this cowardly act.”
Parents separated from their children during the mayhem were told to go to a Holiday Inn, where many youngsters had taken refuge. A number of hotels, including the Holiday Inn and a Travelodge, opened their doors to concertgoers trapped inside the police cordon, providing them with drinks and phone chargers to enable them to contact family members. Residents also offered stranded concertgoers places to stay in their homes.
The confusion and fear in the hours afterward were reflected on social media. One Twitter post asked: “Did anybody see my girlfriend? I lost her in the chaos.”
SMG, the Pennsylvania-based company that manages the Manchester Arena, and Wes Westley, the company’s president and chief executive, described the precautions at the site.
“It is obviously as tight security as anywhere in the States,” he said in an interview. “Backpacks are not allowed. Drinks are taken away from people. You have to go through very strict security to enter the arena.”
The BBC interviewed a man who was waiting outside the arena to pick up his wife and daughter. He recounted that the “whole building shook,” that there was “carnage everywhere,” and that the explosion appeared to come from near the stadium’s ticket area.
Videos posted on Twitter showed concertgoers running and screaming. Hannah Dane, who attended the performance, told The Guardian that she had heard “quite a loud explosion.”
“It shook,” she said. “Then everyone screamed and tried to get out.”
The Manchester Arena opened in 1995 and can hold up to 21,000 spectators; it was not clear how many people were in the crowd for the concert.
Karen Ford told the BBC that she had been leaving the show when the blast occurred. “Everyone was just getting out of their seats and walking toward the stairs when all of a sudden a huge sound, which sounded like an explosion, went off,” she said.
“Everyone tried to push people up the stairs,” Ms. Ford recalled, adding that in the chaos, people tried to push past a woman in a wheelchair as children screamed.
“Just chaos,” she added. “I was trying to tell people to calm down.” She said the masses of people trying to flee created a perilous situation: “We were being crushed.”
Outside, Ms. Ford said, parents awaited children who had attended the concert, checking their smartphones in a panic. “Everyone was trying to find each other,” she said.
While the country and the world reacted to the news of the explosion and deaths with dismay, anger and grief, the British authorities, who have foiled numerous terrorist plots, were probably not surprised.
The terrorist threat level set by MI5, the domestic intelligence service, has been at “severe,” the second-highest level, for months now, meaning officials considered an attack “highly likely.”
While disenchanted young people can be radicalized through extremist websites, officials are particularly worried about the return of hundreds of battle-trained fighters who left Britain and other European countries to join jihadist groups in Syria and Iraq.
Ms. May’s governing Conservative Party announced that it would refrain from campaigning on Tuesday in the June 8 general election, out of respect for the victims. Opposition politicians — Jeremy Corbyn of the Labour Party, Tim Farron of the Liberal Democrats and Nicola Sturgeon of the Scottish National Party — joined Mrs. May in expressing their grief and condolences.
But with the election approaching, Manchester seems bound to become part of the political discourse.
