Google GOOG is developing a ride-hailing service that could eventually rely on self-driving cars, Bloomberg reported Monday. The project would put it on a collision course with Uber, which in just a few years has seized a huge chunk of the existing taxi business.

There is no word on when a Google ride-sharing service would become available to the general public, though Bloomberg reported that the company is testing a version of the service with its employees.

Google’s potential move into the market comes two years after its venture capital arm, Google Ventures, led a massive 2013 investment in Uber that valued it around $3.5 billion. Subsequent funding rounds have valued Uber at more than $40 billion.

Concerned about Google’s possible entry, Uber is considering removing Google’s chief legal officer, David Drummond, from its board of directors, according to Bloomberg, which cited anonymous sources. Drummond has been a board member since 2013.

Meanwhile, Uber is moving forward with plans to develop its own driverless vehicle technology and is building a research facility in Pittsburgh to explore the idea, TechCrunch reported. Autonomous cars would let Uber avoid having to share money from passengers with drivers.

Uber did not immediately respond to requests for comment. Google responded to a request for comment with a link to a tweet the company posted in reply to Bloomberg: “We think you’ll find Uber and Lyft work quite well. We use them all the time.”

A few months ago, Fortune wondered if Google and ride-sharing startup Uber might be on “a collision course” over dueling on-demand delivery services. But the two tech companies could be headed for an even bigger clash.

Uber has already made more than its share of enemies in a series of controversies including by ignoring regulators and taking on taxi companies, some of which have sued to stop the newcomer. Uber and ride-hailing service rival Lyft have exchanged public accusations while competing for customers and drivers. A number of passengers have also accused Uber drivers of questionable conduct, including a woman in Los Angeles who accused her Uber driver of sexually assaulting her this week.

In other words, a battle with Google would only be the latest conflict for Uber.

(UPDATE: This article has been updated to include a response from Google.)

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