Leading figures from the world of motorsport have paid tribute to Marco Simoncelli, who was killed on Sunday in MotoGP's Malaysian Grand Prix.
The 24-year-old Italian, who had been the sensation of the 2011 season, was struck by following riders after falling from his bike on lap two of the Sepang race.
He was pronounced dead at the circuit's medical centre shortly afterwards as a result of the injuries sustained.
F1 champ Lewis Hamilton was one of the first to send his condolences.
"RIP Marco Simoncelli. My thoughts are with his family, friends and team at this extremely sad time. Another tragic loss at such an early age," he posted on Twitter.
Fellow driver Jenson Button also paid tribute.
"R.I.P Marco... Such an exciting talent lost. My thoughts are with his family, friends and everyone involved in MotoGP. Motorsport can be so cruel..."
Seven-time MotoGP world champion Valentino Rossi was involved in the collision which killed his fellow Italian.
"Simoncelli for me was like a youngest brother," he said on Twitter.
"So strong on track and so sweet in the normal life. I will miss him a lot."