A woman was killed Sunday night in Tempe, Arizona, after she was hit by a self-driving car operated by Uber. It is the first known pedestrian death caused by a self-driving car.

The woman was crossing the street but was not in the crosswalk, according to reports. According to a statement issued by Tempe police obtained by the New York Times, a human safety driver was at the wheel when the car was operating autonomously. The driver and the car failed to react in time to prevent the fatality.

The woman's name has not been released. Tempe police didn't immediately respond for comment Monday morning.

According to a report in The New York Times, an Uber spokesman said the company is cooperating with local authorities. The company also said it is suspending the testing of its self-driving car program in Tempe, Pittsburgh, San Francisco, and Toronto.

This is not the first death in the U.S. due to autonomous driving. An Ohio man in a Tesla Model S died in Florida in 2016 when his Tesla hit a white semi truck while driving in the semi-autonomous Autopilot mode. The vehicle failed to see the white truck against the bright sky.

Uber is testing more than self-driving cars. The company has had a fleet of self-driving semi-trucks in operation in Arizona for a couple months after its acquisition of the company Otto.