At least one person was injured and many more were injured when the roof of the Apollo Theatre in Belvidere, Ill. collapsed on Friday night (March 31).

The sold-out concert featured a lineup of metal bands, including headliner Morbid Angel and support acts Revocation, Skeletal Remains and Crypta.

According to CBS Chicago, “the collapse happened about 30 minutes into the concert. The first call came in as a mass-casualty collapse.”

More than 20 ambulances were reportedly called to the scene. According to multiple reports, around 260 people were in attendance. Opening band Crypta had recently ended their set and many fans had left the building to smoke. The storm broke suddenly, with heavy rain sending most people back inside. The wind speed increased to storm force over a matter of seconds and the roof collapsed within a minute. Fire chief Shawn Schadle said that at least 28 people had been taken to hospital, five of them in a serious condition. None of the performing musicians or crew were injured. Videos posted to social media show concert patrons helping pull others from the rubble.

“I just got down and I stayed down until the building wasn’t rattling any more,“ one eyewitness told Belvidere News. “I did watch a lot of people getting in there… getting people out. A bunch of people went over and they lifted the piece of the ceiling off of whoever was under there… those people deserve recognition.”

The Belvidere area was hit with hard storms, including heavy rain, hail and 90 mile per hour winds, all of which may have contributed to the collapse. Other parts of the state reported tornadoes throughout the day.

“Tonight’s show is Canceled due to a Tornado that hit the Venue,” Morbid Angel wrote in a message to their Facebook page. “We ask anyone who is still traveling to the venue to please seek shelter and stay safe. We are currently sheltering in place, and want to extend our support and hope that everyone at the show tonight is safe. Right now our focus is making sure everyone in the venue tonight is ok and gets home.”

In a statement, Illinois Gov. JB Pritzker noted that he was “closely monitoring the roof collapse at the Apollo Theatre.”

“I’ve been in touch with officials for updates and to direct any available resources we can. As we learn more, please follow the guidance of all local authorities,” the politician wrote.

This is an ongoing story and will be updated as more information becomes available.