Team Goeleven Kawasaki motorcyclist Andrea Antonelli has died following a crash during a World Supersport race at the Moscow Raceway, World Superbike organisers have confirmed.
In wet and rainy conditions, 25-year-old Italian Antonelli lost control of his Kawasaki bike on the first lap and his head collided with the Honda of countryman Lorenzo Zanetti, who was also unseated.
Antonelli was immediately transported to the course's medical centre but, given the seriousness of his injuries, it was decided not to risk helicopter transport to the nearest hospital and he died after failing to regain consciousness.
The Supersport race was stopped and postponed for an afternoon restart before being cancelled indefinitely. The second World Superbike event was also cancelled after Marco Melandri (BMW Motorrad Goldbet) had won the morning's race from Chaz Davies.
A statement published on worldsbk.com read: "During today's FIM World Supersport race, at 1.32pm Italian rider Andrea Antonelli (Team Goeleven Kawasaki) suffered a serious accident on the straight between Turn 14 and Turn 15 wherein he sustained critical injuries.
"The race was stopped with the red flag and the rider was immediately taken to an ambulance where the medical staff worked to resuscitate him.
"Despite their efforts, Andrea sadly succumbed to his injuries at 2.10pm local time.
"FIM, Dorna and YMS Promotion decided to cancel all activities scheduled for the rest of the day.
"Everyone involved in motorcycle championships extends its deepest condolences to Andrea's family, friends, team and the Italian Federation at this tragic loss."
The Castiglione di Lago rider, who achieved 14 podium finishes in European Superstock 600 and 1000 races, had started from second on the grid in Moscow.
Antonelli becomes the second Italian to die in competition in two years after MotoGP rider Marco Simoncelli was killed during the 2011 Malaysian Grand Prix in Sepang.
One of the doctors to work on Antonelli following his accident, Dr Massimo Corbascio, believes there was "absolutely nothing" the emergency clinic's team could do to revive him.
He told the Gazzetta dello Sport: "(Yamaha rider Massimo) Roccoli was hit by Andrea, who had already fallen. Then Zanetti was going 250km per hour and was not able to avoid him.
"He's said himself he hit 'something green' before he fell off and was wounded himself. If a rider is hit in the skull by a bike that weighs 160kg at 250km, what can you do?
"He has gone to keep Marco Simoncelli company. We tried to revive Andrea immediately, but there was absolutely nothing we could do.
"In these cases, even if you intubate someone and take them to the intensive care unit - he remains a body attached to a machine with no brain, there's just blood in the brain."