A 13-year-old motorcycle racer was run over and killed Sunday after falling off his bike during a warmup lap at Indianapolis Motor Speedway.

American Peter Lenz suffered "traumatic injuries" and was pronounced dead by the Indiana coroner on Sunday.

After his crash, Lenz was struck by a 12-year-old racer who was not hurt.

Lenz was taken off the track in a stretcher and rushed to a nearby hospital where he died three hours later. The coroner's office said he died from blunt force trauma.

"On behalf of the Lenz family, we would like to thank Peter's friends and supporters for all their help throughout the years," the family said in a statement Sunday.

"We are deeply saddened by this tragic loss, but know Peter is racing even faster in the sky.

"Our thoughts and prayers are now with the other racer and his family, who were also involved in this tragedy."

Despite his young age, Lenz's family said he was an experienced junior rider. He had won nine national championships in his six years of riding bikes.

He is the first competitor to die at the famous Indianapolis Motor Speedway since 2003 when Tony Renna was killed in an IndyCar race and the youngest in the history of the 101 year old race track.

"Words cannot adequately express the sadness of our company and our employees about this tragic incident," said Jeff Belskus, president and chief executive office of the Speedway Corp.

Lenz was scheduled to race in a US Grand Prix Racers Union event ahead of the MotoGP Series events Sunday.

Lenz was a rising star on the training circuit for riders ages 12-18. He had won three races in the series and his social networking Facebook page states he had 125 victories and 35 additional podium finishes in his career.

Lenz had several surgeries last year which cut his season short. His website, PeterLenz.com, reported that he broke several bones in 2009. The list included a broken tibia and fibula just above the boot, a broken femur and a broken humerus above the elbow.

Even the world's elite racers were put to the test by difficult racing conditions Sunday, who said the course turned bumpy because of the heat.

Sunday's Moto2 race was cut short after a massive smash on the opening lap that cut the field by four. And reigning world champion Valentino Rossi also fell of his bike during a warmup session Sunday. Rossi fell a total of four times including the warmup and race.

"This was the most difficult race for everyone," MotoGP winner Dani Pedrosa said. "The conditions were very hard because of the heat and the asphalt was very greasy."

Organizers said they didn't cancel the USGPRU race because they didn't know the extent of Lenz's injuries.

An autopsy is expected to be performed on Monday.