A 14-year-old Spanish motorcycle racer was killed on Sunday during a race at the Motorland circuit in the Aragonese town of Alcaniz, organisers announced.
"We regret to announce that our Hawkers European Talent Cup rider, Hugo Millan, has died after a terrible accident," said a statement on the Cuna de Campeones website.
Millan, who was competing in the European Talent Cup, fell off his bike 13 laps from the finish.
According to the Spanish newspaper Marca, the bike behind could not avoid Millan, hitting him in the back and neck area.
The red flag was immediately waved, stopping the race and, after receiving emergency treatment on the track, Millan was airlifted by helicopter to Zaragoza Hospital.
The European Talent Cup is one of the categories of the FIM CEV, an international championship for teenage riders from which they can make the step up to the professional circuit.
Six-time MotoGP world champion Marc Marquez tweeted his condolences.
"My sincere condolences to his family, friends and team," wrote the Spaniard.
Millian's death comes almost three months after Swiss Moto3 rider Jason Dupasquier, 19, died from injuries he sustained in a three-bike crash during qualifying for the Italian Grand Prix at Mugello.
Dupasquier, whose father Philippe was a former motocross rider, was in his second season in Moto3.