In the wake of a fatal collision involving an Uber autonomous vehicle and a pedestrian, Ariz. Gov. Doug Ducey said he is suspending Uber from testing autonomous vehicles in the state.

Ducey told the company in a letter that he is suspending Uber’s “ability to test and operate autonomous vehicles on Arizona’s public roadways,” according to ABC News.

In a series of tweets, Ducey said self-driving technology holds “enormous promise” but the state “will take strong action against any company or operator that does not demonstrate they are ready for primetime.”

I was personally very disturbed by the video Tempe Police released. I know others were too. Raises questions that need to be answered. 2 federal investigations will help. These are independent and led by experts. I want to see the facts. 1/4

— Doug Ducey (@DougDucey) March 27, 2018