After a crowd surge during Travis Scott’s Friday night performance at Houston’s Astroworld music festival, at least eight people were killed and many more were injured.

50,000 people attended the first night of this weekend’s sold-out Astroworld music event at NRG Stadium and “the crowd began to compress toward the front of the stage” at around 9:30 p.m. local time, according to Houston Fire Chief Sam Pena.

“That caused some panic, and it started causing some injuries. People began to fall out, become unconscious, and it created additional panic,” he said, adding that a “cause of death was not yet known for the eight victims but would be determined.”

Authorities reported twenty-five individuals were sent to the hospital, including one child as young as ten years old. Eleven patients were sent to the hospital in cardiac arrest, according to Pena.

The youngest of those killed was 14, according to city mayor Sylvester Turner, who spoke at a press conference on Saturday evening. Another was 16, two were 21, two were 23, one was 27, and the final person was of uncertain age since he could not be identified right away.

“Nothing of this magnitude that any of us can recall, and certainly that I can recall, has taken place in this city,” Turner added.

Houston Police Chief Troy Finner told reporters on Friday that several of the deceased lacked identification.

A command center for missing persons information was put up at a neighboring hotel. Officials said no one had been reported missing as of Saturday afternoon.

Scott indicated that he was “absolutely devastated” by the events.

“My prayers go out to the families and all those impacted by what happened at Astroworld Festival,” he said in a tweet on Saturday. “Houston PD has my total support as they continue to look into the tragic loss of life.”

“I am committed to working together with the Houston community to heal and support the families in need,” he added.

The festival was canceled for Saturday after it finished early Friday night.

An NRG Park spokesperson said they were “deeply saddened by the heartbreaking loss of life and pain experienced by all those impacted by this tragedy.”

“We are fully cooperating and working closely with police and local authorities as they investigate how this tragedy occurred at the Astroworld Festival,” the spokesperson said.

One concertgoer claimed she was pushed “very aggressively.”

“It was intense, it was intense,” the concertgoer told “Good Morning America.” “We were seeing people getting pulled out of the crowd, and we would see some of these people unconscious.”

Houston Police Chief Troy Finner also acknowledged that his department is currently conducting a “criminal investigation” that will include both the homicide and narcotics divisions. He said 25 individuals were detained at the event, including 23 “trespassers” who weren’t supposed to be there.

Finner also addressed reports of drug usage during the show, including a “narrative” of someone injecting narcotics in people.

He said one medical staff member told investigators that a security guard went unconscious after feeling a “prick in his neck.” That officer — who investigators have yet to interview — was reportedly revived after being given Narcan, and did indeed have a prick in his neck consistent with the mark of an injection, Finner said.

Officials highlighted that the origin of the spike during Scott’s concert was still unknown as of Saturday morning, while spectators have speculated on what caused it since then. While covering the event for the Associated Press, freelance photographer Amy Harris said she noticed a “aggressive” attitude throughout the day, with concertgoers apparently shoving one other, storming the stage, and crossing barricades to VIP areas.