Aug. 18 (UPI) — More than 20 people were hurt when a Ferris wheel caught fire at a music festival in Germany.

Saxony police said the ride caught fire shortly after 9 p.m. local time Saturday, for reasons that are still unclear.

Smoke was billowing into the air at the Highfield Festival near the city of Leipzig, in eastern Germany about 117 miles south of Berlin.

One of the gondolas of the Ferris wheel caught fire and it spread to another one, DW reported.

DPA reported a festival goer from Cologne said that the Ferris wheel suddenly sped up with the burning gondolas were at the very top of the wheel.

The annual four-day event draws up to 30,000 concertgoers.

Among those injured, four suffered from burn injuries and another was treated for injuries from falling.

Eighteen people including first responders, police officers and others on the ride came into contact with smoke and were taken to hospitals.

German rapper Ski Aggu was performing onstage at the festival.

Shortly after 10 p.m. Saturday, performances restarted.