There were conflicting reports about whether Chicago-based indie rock band Smith Westerns was playing at the time but they later tweeted they all were fine.
Jared Leto, actor-turned-frontman of 30 Seconds to Mars, was due to headline the program with his band later, along with the Foo Fighters. Eminem was listed as the main act in the line-up for Friday. Hasselt Mayor Hilde Claes said four persons were killed and 40 injured, according to RTBF. Tens of thousands had reportedly flocked to the site for the annual Pukkelpop festival.
"Stage collapsed max almost got crushed by the tress (sic). I hope pukkelpop has insurance bc all our sh*t is broke," the Smith Westerns tweeted. "Praying no one got hurt."
The stage collapse and deaths followed a similar incident last Sunday in Indianapolis, Ind., where a huge storm caused the collapse of a towering outdoor stage at the Indiana State Fair, killing five and sending at least 40 to hospitals.
It also marked the second straight year of deaths at the Pukkelpop festival. In 2010, a sound engineer died of a heart attack and a rock singer, Charles Haddon, committed suicide by jumping from the top of a transmission tower after his group performed.