Antonelli, 25, raced in the supersport division of high-speed motorcycles. He crashed on the opening lap of Sunday's race in rainy weather and was struck by another rider, according to media reports.
Antonelli "was immediately taken to an ambulance where the medical staff worked to resuscitate him," FIM World Championship said in a news release. "Despite their efforts, Andrea sadly succumbed to his injuries at 2:10 p.m. local time."
Race organizers then canceled the race and other remaining events scheduled Sunday.
Antonelli raced a Kawasaki motorcycle for Team Go Eleven of Italy.