One of Google's self-driving cars got into an accident earlier this week, but the vendor claimed the auto-pilot-equipped Toyota Prius was in manual driver mode when the accident happened.

The news initially came from a Jalopnik reader who sent the auto blog a photo of the car with another Prius near Google's California headquarters. The accident appears to be minor and no one was hurt, judging by the photo, but exact details remain unknown.

Jalopnik and many other websites reported the incident as the "first caused by Google's self-driving car," which prompted a quick response from a Google spokesperson. In a statement sent to Business Insider, that spokesperson clarified that the car (and Google's software) wasn't to blame for the Prius-on-Prius accident; its driver was.

"Safety is our top priority. One of our goals is to prevent fender-benders like this one, which occurred while a person was manually driving the car," the spokesperson said.

Google's self-driving cars use a combination of video cameras, radar sensors, and laser range finders to see other cars and rely on Google Maps and Earth to navigate the road, Google Software Engineer Sebastian Thrun said in a blog post in October 2010. He also pointed out that the autonomous cars had trained drivers and software engineers inside during testing.