You’re probably familiar with Waymo and Cruise, the two driverless ride-hailing companies who have recently been given a green light to expand their operations. But you might not be aware that there are 40 firms licensed to test autonomous cars in California, and that one quarter of those are from China.

The activities of companies like Pony.ai, Apollo, WeRide and AutoX are less well known because their tests are running on a smaller scale and they haven’t been involved in any high-profile crashes. But U.S. lawmakers have definitely noticed their presence and some members of Congress are concerned enough that they’re calling for these firms’ activities to be curtailed.

Some critics have expressed worries over the amount and type of data Chinese companies might be collecting, much like they’re unhappy with the presence of other Chinese firms such as TikTok, NBC News reports. Some of those objecting to the driverless startups are simply unhappy with China’s human rights records, while other actually believe fleets of robotaxis could be used against America if the country ever became engaged in armed conflict with China.

Related: Over A Dozen Cruise Robotaxis Get Stuck In Dystopian Traffic Jam In Austin

 Could Chinese Self-Driving Cars Go On A Programed Killing Spree In America? Some Lawmakers Think So

One former member of the Google self-driving car project that became Waymo said that a fleet of robotaxis could be “a potent weapon” capable of purposely crashing into and killing innocent people if the two nations ever came to blows.

Though that last viewpoint is at the extreme end of the list of fears, and not necessarily shared by most members of congress, some politicians were sufficiently concerned about the data angle that a bipartisan group of four members asked the Biden administration to launch an investigation. The group pointed out that none of the Chinese companies active in testing driverless cars in the U.S. were participating in the voluntary federal program to track such tests.

But more noteworthy is the fact that while the U.S. has welcomed Chinese startups wanting to engage in driverless programs on American soil, no American companies are able to do the same in China, NBC News says.

“Their autonomous vehicle companies are piloting on our roads right now; we cannot,” Commerce Secretary Gina Raimondo told a House hearing recently after a visit to China. “Let’s level the playing field.”