San Francisco Mayor Ed Lee and the California State Attorney General's Office have ordered Uber to put the brakes on its self-driving cars. Uber, which began testing self-driving cars last week, has been asked by the California Department of Motor Vehicles to halt its program as well. The issue? Uber never received proper permits for testing its self-driving vehicles on city streets, according to the San Francisco Chronicle.

Obtaining permits is for public safety, not just for following the law, Mayor Lee said in a statement to the Chronicle. The state Attorney General told Uber on Friday to stop testing immediately or face an injunction or other action, reports Tech Crunch.

The cost of permits or the process to get one is not the issue. Autonomous vehicle testing permits only cost $150, according to PYMTS. The DMV has issued permits for over 20 other companies. The ride-sharing company continues to assert that it doesn’t need special permits since a backup driver also is behind the wheel.

During a media conference call on Friday, Uber again emphasized its stance, according to the Wall Street Journal, saying its cars are not totally autonomous and are more like Tesla Motors’ autopilot feature that can take over steering but isn’t relied upon, and doesn’t need a permit.

The recent backlash also stems from online video showing one of the cars blowing through a red light. Uber said it was human error for failing to properly monitor the technology and has since disciplined the driver. The car wasn’t one in its pilot program and didn’t have any passengers, according to the Chronicle.