Renna came seventh in last season's Indy 500
Indy Racing League driver Tony Renna has been killed during testing at the Indianapolis Motor Speedway.
He crashed into the outside wall at 220mph while exiting the track's third turn in his Team Ganassi car.
Reports said his car jumped sideways and became airborne, clearing a concrete wall and crashing into a fence where it broke apart.
The 26-year-old was transported to the city's Methodist Hospital, where he was pronounced dead on arrival.
IMS boss Tony George led the tributes to Renna, saying: "Tony Renna was a rising star in IndyCar racing. All of us involved in racing feel a great loss.
"Our prayers and best wishes go out to his family, friends, team and fans."
Renna is the 67th person killed at the track since it opened in 1909.
The last driver to die at Indianapolis was Scott Brayton, who died in a crash during practice in 1996.
Renna's fatal crash comes little more than a week after fellow IRL driver Kenny Brack suffered severe injuries in an accident at the Texas 500.
Renna finished seventh in the Indy 500 in May, and
joined the Ganassi Racing team this month,
replacing Tomas Scheckter.
Ganassi's lead driver, Scott Dixon, won the recent IRL
championship and was among
three drivers who began tire tests at the Speedway.
The Florida racer made his debut in the IRL last year as a substitute driver for Al
Unser Jr, who himself is recovering from a serious driving accident
He competed in seven IndyCar Series races with Kelley
Racing, with five top-10 finishes, including a career-best
fourth in 2002 at Michigan.