A woman was killed by an Uber self-driving car that was operating in autonomous mode, in Tempe, Arizona. The fatal accident occurred either late Sunday or early Monday, according to the New York Times.

The Tempe Police Department said 49-year-old Elaine Herzberg was crossing the street outside of a crosswalk when she was struck. Police added that she “was transported to a local area hospital where she passed away from her injuries.” The woman’s name has not yet been released.

This is the first time a pedestrian has been killed by an autonomous car on public roads. In 2016, a man was killed when his Tesla Model S crashed into a tractor-trailer while on autopilot—a different technology than Uber’s self-driving software—at 70 miles per hour. Uber has suspended testing of its autonomous vehicles in Phoenix, Pittsburgh, San Francisco, and Toronto. We don’t know if and when it plans to resume its pilot programs.

Arizona has been a petri dish for self-driving car technology belonging to Uber, GM, Waymo, and Intel. Until now, 600 autonomous cars were operating in the state, according to Governor Doug Ducey. Earlier this month, Ducey issued an executive order allowing fully driverless cars—ones without human operators behind the wheel—to drive on Arizona roads, so long as they comply with federal and state safety standards. The order also requires autonomous car companies to submit to accident reporting, though we don’t know yet what information Uber is compelled to make public about the collision.

“Our hearts go out to the victim’s family. We are fully cooperating with local authorities in their investigation of this incident,” Uber said in a statement.

Uber did not answer my questions about long its pilot programs will remain suspended, and what type of accident data the company will share with Arizona authorities and the public.

The National Transportation Safety Board told CNBC that it is investigating the fatal accident.

Unlike other testing grounds, such as California, Arizona does not require autonomous car companies to submit disengagement reports, or instances of a vehicle’s operator taking control of the car.

In 2016, Uber moved its self-driving car program to Arizona, after refusing to apply for the necessary permits to test its vehicles with passengers in San Francisco. The company returned to the city last year, but under the agreement that its autonomous vehicles would only be used for mapping purposes. Uber has also resisted pressure from agencies like the California Department of Motor Vehicles to share more vehicle safety data, specifically regarding crashes.