Uber has been under fire since the moment it opened up its fleet of self-driving SUVs to San Francisco customers on Monday. In addition to multiple reports that the vehicles were spotted running red lights, the company neglected to register for an autonomous vehicle permit with the California DMV, a step that has been taken by 20 of its competitors, including Google and General Motors.

But despite threats of legal action by the DMV and criticism from Mayor Ed Lee, Uber said this afternoon that it's still planning to keep its fleet of 11 self-driving Volvo XC70 SUVs on the road in San Francisco. 

In a conference call, Uber maintained its insistence that the vehicles are not truly autonomous, as each is staffed by a human engineer, who can take over in the event of a malfunction. Uber had been testing the vehicles on San Francisco's streets for about a month after a previous trial in Pittsburgh, but only opened them up to riders on Monday. 

"It's hard to understand why the DMV would require Uber to get a permit," Anthony Levandowski, head of Uber's self-driving program, told reporters in a conference call this afternoon. "Nor is it clear why a permit is required now, even though it was well known that our vehicles have been operating San Francisco for the past month." (Here's Levandowski's full statement on the issue.)

The DMV disagrees with Uber's assessment. In a letter sent to Uber on Monday, it told the company it "must cease" operating without a permit, and threatened legal action if it did not. 

Mayor Ed Lee has also insisted Uber cease operations until it gets a permit. “This is not just a matter of following the law, it’s a matter of public safety,” his spokesperson, Ellen Canale, told the SF Business Times. "The mayor expects Uber to do what is required by law and obtain a permit from the DMV, just like every other company testing autonomous vehicles in San Francisco."

It's not clear whether the DMV and/or the Mayor's Office will now move forward with possible legal action against Uber, or what form that action might take. The company, which is notorious for bypassing regulations to get its way, has paid out $160 million in lawsuits since 2009, according to the Guardian. 

As for the incidents in which self-driving Uber vehicles were seen running red lights, Uber insists that they were caused by the errors of human co-pilots, and that the drivers involved have been suspended. 

Update, 5:29pm: According to a Financial Times reporter, the California Attorney General's office is now also threatening legal action against Uber:

Now California's Attorney General is telling Uber to halt its self-driving cars pilot or it will "seek injunctive &other appropriate relief" pic.twitter.com/cUGxRzob4o

— Tim Bradshaw (@tim) December 17, 2016