Uber said Monday it has paused its testing of autonomous cars, including in Toronto, after a pedestrian fatality overnight in Tempe, Ariz.

A spokesperson for Uber Canada confirmed the company has halted tests in San Francisco, Phoenix, Pittsburgh and Toronto.

Reports from The Associated Press indicate that a self-driving Uber vehicle in Tempe was in autonomous mode with a human operator behind the wheel when it struck a woman who had walked into the street. The woman later died in hospital.

“The vehicle was traveling northbound … when a female walking outside of the crosswalk crossed the road from west to 
east when she was struck by the Uber vehicle,” Tempe police said in a statement.

The New York Times reported that the fatality could be the first known fatality involving a pedestrian struck by an autonomous vehicle on public roads.

The U.S. Transportation Safety Board is looking into the death, Bloomberg said, reporting that NTSB spokesman Eric Weiss said the he hasn’t decided yet whether to open full investigation.

A tweet from Uber chief executive Dara Khosrowshahi expressed condolences to the victim’s family. The company says it is co-operating with police and authorities in an investigation of the fatality.