Marco Simoncelli is killed in MotoGP crash in Malaysia. His death comes one week after Indianapolis 500 winner Dan Wheldon was killed at Las Vegas Motor Speedway.
Medical director Michele Macchiagodena said Simoncelli suffered a "very serious trauma to the head, to the neck and the chest".
The death is the first fatality in MotoGP since Japan's Daijiro Katoh died from injuries sustained at the 2003 Japanese GP while, last year, Japan's Shoya Tomizawa died in a similar crash to Simoncelli in a Moto2 race in San Marino.