The driver of a Tesla vehicle involved in a crash in Minnesota on Saturday has denied that its Autopilot system caused the incident, according to an email released by the automaker on Monday.

The Kandiyohi County Sheriff's Department said in a statement on Sunday that the driver of the 2016 Tesla had said that when he engaged the Autopilot system it caused the vehicle to suddenly accelerate and then roll over, resulting in minor injuries to himself and four passengers.

But the driver said in the email released by Tesla Inc on Monday he believed he had disengaged the Autopilot system at the time of the crash. Tesla shares fell in trading on Monday after the crash was reported.

The driver, David Clark, 58, did not immediately respond to requests for comment.

"I did not intend to put the blame Tesla or the auto pilot system as I am aware that I need to be in control of the vehicle regardless if the auto pilot system is engaged or not," Clark said in an email to the sheriff's department released by Tesla.

The sheriff's department did not immediately respond to a request for comment.

Tesla shares, which fell as low as $313.45 on Monday, rebounded later and were down 2.8 percent at $318.69 in afternoon trading.

Autopilot has faced intense scrutiny in the past from U.S. regulators.

Tesla said in a statement it had "no reason to believe that Autopilot ... worked other than as designed."

"Every time a driver engages Autopilot, they are reminded of their responsibility to remain engaged and to be prepared to take immediate action at all times, and drivers must acknowledge their responsibility to do so before Autopilot is enabled, the auotmaker added.

Joshua Brown, a former Navy SEAL, was killed near Williston, Florida, in May 2016 when his Model S collided with a truck while it was engaged in Autopilot mode.

The incident raised questions about the safety of systems that can perform driving tasks for long stretches with little or no human intervention, but which cannot completely replace human driver.

In January, the U.S. National Highway Traffic Safety Administration said it had found no evidence of defects with Autopilot following Brown's death. (Reporting by David Shepardson; Editing by Tom Brown)