At least eight people have died and many others have been injured in a crowd surge at the Astroworld Festival, in Houston, Texas.
A compression of the crowd toward the stage occurred just after 9pm local time on Friday (5 November) while rapper Travis Scott was performing, Houston Fire Chief Samuel Pena told reporters at a news conference.
The line-up for the festival featured Master P, Yves Tumor, Toro y Moi, Roddy Rich, Lil Baby and festival founder Scott, as well as a surprise appearance from Drake.
"The crowd began to compress towards the front of the stage, and that caused some panic, and it started causing some injuries," the fire chief said.
"People began to fall out, become unconscious, and it created additional panic."
The show was called off shortly after several people began suffering injuries, and the second and final day of the festival has been cancelled.
Officials transported 23 people to the hospital, including 11 who were in cardiac arrest, Pena said.
Around 300 people were treated for injuries such as cuts and bruises at the scene at NRG Park, where a field hospital had been set up.
Approximately 50,000 people were in attendance at the festival, Pena said.
The fire chief added that officials did not immediately know the causes of death for the eight people who died and a medical examiner would investigate. The deceased had not been identified as of early Saturday.
Officials set up a reunification centre at a hotel for family members who had not been able to reach relatives in attendance at the festival.
Astroworld is a two-day music festival that was scheduled to take place on Friday and Saturday in Houston. The event was sold out, according to the Astroworld website.
The event promoters had arranged for medical units to be on scene at the festival, however once the crowd surge began, those units were 'quickly overwhelmed', Pena said.
Earlier in the day, hundreds of people stormed the event's perimeter, knocking down metal detectors and a security screening area, according to AB13.
However, Houston Police Chief Troy Finner said the two incidents were not related and he urged people not to jump to conclusions as to what caused the surge.
"I think it's very important that none of us speculate. Nobody has all the answers tonight," Finner said.
"We're going to do an investigation and find out because it's not fair to the producers, to anybody else involved, until we determine what happened, what caused the surge.
"We don't know, but we will find out."