Uber has removed its self-driving cars from San Francisco streets after California regulators cracked down on the programme because the company had not obtained a permit to test autonomous vehicles.

The California Department of Motor Vehicles said on Wednesday it revoked the registration of 16 Uber self-driving cars after a weeklong battle with the ride-services company.

The regulator had demanded that Uber obtain a permit to test its self-driving cars on public roads - just as 20 other companies, including Tesla and Ford, have done - but Uber said it wasn't obligated to do so because there is a safety driver at the wheel.

"We're now looking at where we can redeploy these cars but remain 100 percent committed to California and will be redoubling our efforts to develop workable statewide rules," a spokeswoman said in a statement.

Uber has argued that its cars are not able to drive without a person monitoring them - a driver and an engineer are in the front seats to take over frequently in situations such as a construction zone or pedestrian crossing - so the law does not apply.