A self-driving car from Uber Technologies Inc. hit and killed a woman in Tempe, Arizona, on Sunday evening, what is likely the first pedestrian fatality involving a driverless vehicle.

The woman was crossing the road when the Uber vehicle, operating in autonomous mode, struck her, according to the Tempe Police Department. She was transferred to a local hospital where she died from her injuries. “Uber is assisting and this is still an active investigation,” Liliana Duran, a spokeswoman from the Tempe police, said in an emailed statement.

Uber said on Monday that it was halting tests of all its autonomous vehicles in Pittsburgh, San Francisco, Toronto and the greater Phoenix area. “Our hearts go out to the victim’s family,” a company spokeswoman said in a statement. “We are fully cooperating with local authorities in their investigation of this incident.”