The company wrote on its website that the man driving the Model S collided with a turning tractor-trailer when the car's autopilot camera failed to distinguish between the white side of the oncoming vehicle and the brightly lit sky.

The accident occurred May 7 - most of the small hatchback slid underneath the truck and out the other side, but the bottom of the trailer struck the windshield and caused severe damage to the car and its driver.

Tesla has ordered an investigation into the exact problem that caused the crash, which resulted in the first known fatality in what the company reports as 130 million miles of autopilot driving. The company said this represented a safer record than human averages in the US or the world as a whole.

Tesla's five-door Model S first launched in 2012

The car's autopilot mode cannot be engaged unless the driver's hands remain on the steering wheel.

Tesla orders investigation

"It is important to note that Tesla disables Autopilot by default and requires explicit acknowledgement that the system is new technology and still in a public beta phase before it can be enabled," the company said.

Tesla founder Elon Musk expressed "our condolences for the tragic loss" to the family of the victim.

Tesla shares fell as much as 3 percent in after-hours trading amid the news. The manufacturer of high-performance electric cars launched Autopilot in October 2015, and is in the Beta phase of testing.

"Autopilot is getting better all the time, but it is not perfect and still requires the driver to remain alert," Tesla said. "Nonetheless, when used in conjunction with driver oversight, the data is unequivocal that Autopilot reduces driver workload and results in a statistically significant improvement in safety when compared to purely manual driving."

es/msh (AP, dpa)