(BLOOMBERG) — Uber Technologies Inc. halted autonomous vehicle tests after one of its cars struck and killed a woman in Tempe, Arizona, in what is likely the first pedestrian fatality involving the technology.

The woman was crossing the road outside of a crosswalk when the Uber vehicle, operating in autonomous mode under the supervision of a human safety driver, 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 pausing 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.”

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