At least 28 fans and one driver were injured after a multi-car crash at the Daytona speedway when car debris flew into the crowd near the end of the Nationwide NASCAR race.
Race officials said 14 fans were sent to nearby hospitals, with another 14 being treated at the Florida speedway, which will host the prestigious Daytona 500 race on Sunday.
Driver Michael Annett of the Richard Petty Motorsports team was being treated at the Halifax Health Medical Center in Daytona Beach and would be kept for observation, the team said in a statement.
Joie Chitwood, president of the Daytona International Speedway, said Sunday's main race would go ahead despite the incident.
"First and foremost, our thoughts and prayers are with our race fans," Chitwood said.
"Following the incident, we responded appropriately according to our safety protocols and had emergency medical personnel at the incident immediately.
"We transported 14 people off property and 14 were treated at our on-track care center. We are in the process of repairing the facility, and we will be ready to go racing tomorrow," added Chitwood.
Debris from the 10-car crash flew into the spectator area and amid chaotic scenes, some fans were taken away on stretchers.
The crash sent driver Kyle Larson's car airborne, although he climbed out of the wreckage afterward unhurt.
Dayton Police Department spokesman Jimmie Flynt said 11 people were taken to Halifax Health Medical Center, two of them with serious injuries, and one patient to Florida Hospital Memorial Medical Center in Daytona Beach. Florida Hospital spokeswoman Lindsay Rew said three more patients were expected there.
Annett was transported to a hospital after complaining of pain in his chest and sternum and was treated for bruising on his chest and underwent a CT Scan.
NASCAR's vice president of race operations, Steve O'Donnell, said that the fencing, which was ripped through by the flying debris, was being replaced and the incident would be reviewed.
"We're very confident that we'll be ready for tomorrow's event with the 55th running of the Daytona, but as with any of these incidents, we'll conduct a thorough review, we'll work closely with the tracks as we do for all our events, learn what we can and see what we can apply in the future," he said.
Tony Stewart won the race on Saturday, which is the curtain-raiser for American stock car racing's biggest event on Sunday, which will feature Danica Patrick as the first woman to start on the pole position.