At least eight people are dead and many others were injured after a crowd surge during Travis Scott’s Astroworld music festival in Houston, Texas.

Houston Mayor Sylvester Turner confirmed the news in a press conference Saturday afternoon: six of the eight victims were in their 20s; two were 14 and 16 years old, respectively. Of the additional 17 people that were transported to local hospitals, 13 remain hospitalized (five of which are under the age of 18), and four have been discharged. 

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

Houston Fire Chief Sam Peña said the crowd started to rush toward the stage around 9:15 p.m. CT. People started passing out, inciting more panic, at which point the Houston Police Department declared a mass casualty incident.

“The crowd for whatever reason began to push and surge towards the front of the stage, which caused the people in the front to be compressed – they were unable to escape that situation,” Peña said during a news conference early Saturday morning.

Authorities are investigating “what caused, one, the issue of the crowd surge, and two, what prevented people from being able to escape that situation,” he added.

Festival organizers took to social media Saturday morning to release the following statement: “Our hearts are with the Astroworld Festival family tonight – especially those we lost and their loved ones,” the statement read. “We are focused on supporting local officials however we can. With that in mind the festival will no longer be held on Saturday. As authorities mentioned in their press conference earlier, they are looking into the series of cardiac arrests that took place. If you have any relevant information on this, please reach out to Houston Police. Thank you to our partners at the Houston Police Department, Fire Department, and NRG Park for their response and support.”

Houston Police said Saturday that they are investigating “whether the casualties stemmed were drug-related.” After TMZ reported that a key person involved with the festival alleges “someone in the crowd went crazy and began injecting people with some sort of drug, which caused panic and then a surge,” Chief of Police Troy Finner revealed that a security member at the event lost consciousness after feeling a prick in his neck. He was eventually revived with Narcan, according to Finner, and medical staff spotted a mark on him that could have been from an injection.

One attendee told Rolling Stone they weren’t sure that anyone injected others with drugs.

They’re trying to blame drugs,” Madeline Eskins said. “And I will level with you, I don’t think this was caused by drug use. Could it have been a contributing factor? Sure. Will they find drugs in the bodies of those passed away? Maybe. But people were getting suffocated. People were getting trampled. A lot of these trauma-based injuries. One dude had his face smashed in. He was bleeding from his nose, face, and mouth. Which I guess drugs can cause, but so can getting trampled.”

Video from the event, reported by Variety, showed attendees climbing to where camera crew members were filming for an Apple Music stream and explaining what they saw in the crowd, only for their cries for help to go unresponded. Shareen Memon, a 25-year-old who attended the show, told the Houston Chronicle that people were “just pushing against the barrier.”

“Everything was calm until Travis came out — it went crazy,” Memon recalled. “At one point you couldn’t even breathe and that’s when I knew. As soon as that song ‘Highest in the Room’ was over that’s when we started going out. Even when we were trying to get out people weren’t letting us go past them.”