HOUSTON (AP) — The crowd at a Houston music festival surged violently toward the stage during a performance by rapper Travis Scott, squeezing fans so tightly together that they could not breathe or move their arms, witnesses said Saturday, hours after at least eight people died in the chaos.

The pandemonium unfolded Friday evening at Astroworld, a sold-out, two-day event at the NRG Park stadium. An estimated 50,000 people were in attendance. It was not clear what set the crowd in motion.

Houston Fire Chief Samuel Peña said the crowd “began to compress towards the front of the stage” which triggered panic and caused some injuries. Then “people began to fall out, become unconscious, and it created additional panic.”

Seventeen people were taken to hospitals, including 11 who were in cardiac arrest, Peña said, and “scores of individuals” were injured.

Witnesses reported lots of pushing and shoving during the performances leading up to Scott’s set.

When Scott took the stage, the crowd seemed to rush to the front, trying to get closer to the stage, said Nick Johnson, a high school senior from the Houston suburb of Friendswood who was at the concert with friends.

“It just got worse and worse. Everyone was like you just can’t breathe,” said Johnson, who was near the front of the stage in the middle part of the crowd.

Johnson said fans started to crush each other, and people started screaming. He said it felt like 100 degrees in the crowd, which was so thick that he and his friends could not move.

“Everyone was passing out around you, and everyone was trying to help each other. But you just couldn’t move. You couldn’t do anything. You can’t even pick your arms up,” Johnson said.

Scott seemed to be aware that something was going on in the crowd, but he might not have understood the severity of the situation, Johnson said.

On video posted to social media, Scott could be seen stopping the concert at one point and asking for aid for someone in the audience: “Security, somebody help real quick.”

In a tweet posted Saturday, Scott said he was “absolutely devastated by what took place last night.” He pledged to work “together with the Houston community to heal and support the families in need.”

Houston Police Executive Assistant Chief Larry Satterwhite, who was near the front of the crowd, said the surge “happened all at once.”

“Suddenly we had several people down on the ground, experiencing some type of cardiac arrest or some type of medical episode,” Satterwhite said. “And so we immediately started doing CPR and moving people right then.”

Satterwhite said he quickly met with promoters, who agreed to end the event “in the interest of public safety.”

Amy Harris, a freelance photographer for The Associated Press, described an “aggressive” crowd atmosphere throughout the day because of the way fans were behaving — pushing and rushing the stage barricades and prohibited VIP and admission areas.

“It was definitely the most chaotic festival environment that I’ve been in,” Harris said. “I felt uneasy all day.”

She got trapped behind a barricade while photographing performer Don Toliver because about 300 fans rushed the area. They ended up behind the security barricade with her.

Harris said she encountered a similar scene at a different stage for the main act. She left the media pit after three songs because of the disorder, which resulted in people being pulled over the security barricade to receive medical attention.

At one point, Gerardo Abad-Garcia was pressed so tightly into the crowd that he could not move his arms off his chest. During Toliver’s performance, which came before Scott’s appearance, he started getting concerned for his safety.

“I just couldn’t breathe. I was being compressed,” he said. A security guard helped him and others climb a fence and get out.

He described the crowd during Scott’s set as a wave that was “going forward and backward.”

Some people lost their shoes, and the ground was littered with clothing, water bottles and other trash. He said some people tried to help those who were passed out on the ground, while other concertgoers seemed to ignore them and continued watching the show.

After Scott’s concert, Abad-Garcia saw medical personnel performing CPR on someone who appeared to be unconscious as the person was taken away on a golf cart.

Houston Police Chief Troy Finner urged people not to jump to conclusions about what caused the surge.

“I think it’s very important that none of us speculate. Nobody has all the answers tonight,” Finner said.

Authorities did not immediately know the causes of death, and the dead were not immediately identified. A medical examiner planned to investigate.

Scott, one of music’s biggest young stars, found the Astroworld Festival in 2018, and it has taken place at the former site of Six Flags AstroWorld each year since, except for 2020 because of the coronavirus pandemic. The 29-year-old Houston native has been nominated for eight Grammy Awards. He has a 3-year-old daughter with Kylie Jenner, who announced in September that she’s pregnant with their second child.

Drake joined Scott on-stage at the concert — which was livestreamed by Apple Music — and posted photos to Instagram after the performance.

Officials set up a reunification center at a hotel for family members who were unable to reach relatives at the event. Authorities sought to connect families with fans who were taken to the hospital, “some as young as 10” years old, said Harris County Judge Lina Hidalgo, the county’s top elected official.

The deaths called to mind a 1979 concert by The Who where 11 people died and about two dozen were injured as thousands of fans tried to get into Cincinnati’s Riverfront Coliseum.

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