An Italian karter involved in “disturbing events” at a race track says he has quit the sport.
Luca Corberi, 23, threw his bumper at opponent Paolo Ippolito in anger after crashing at the Karting KZ World Championships in Lonato, northern Italy, on Sunday.
Post-race footage then showed a fight breaking out.
“I have decided not to take part in any other motorsport competition for the rest of my life,” Corberi said.
“There are no excuses to explain why I’ve done such a disgraceful act,” he added in a Facebook post.
“This episode will be remembered as one of the worst in our sport and that’s something I’ll never forget.”
Motor racing’s governing body, the FIA, said it is investigating and added it was “deeply concerned by the disturbing events involving drivers, team members and track officials”.
Footage of the incident had led to widespread criticism of Corberi and ex-Formula 1 champion Jenson Button was among those calling for tough sanctions on the driver.
“This behaviour is unacceptable in our sport,” said FIA Karting president Felipe Massa.