General Motors should be prepared to acknowledge that more than 13 people died as a result of faulty ignition switches installed in its vehicles, the head of the National Highway Traffic Safety Administration said.

The company was aware of problems with the faulty switches, which can disable the vehicles’ air bags, and owes “straight answers” to the families of the victims — however many they may be.

“GM knew about the safety defect, but did not act to protect Americans from that defect until this year,” NHTSA acting administrator David Friedman said in a statement. “NHTSA has been assisting families by identifying whether or not their loved ones are in the number counted by GM. The final death toll associated with this safety defect is not known to NHTSA, but we believe it’s likely that more than 13 lives were lost.”

The Detroit automaker on Tuesday repeated its position.

“To the best of our knowledge, there have been 13 driver or front-seat occupant fatalities that may be related to the ignition-switch defect,” the company said. “That’s after a thorough analysis of the information available to us.”

GM has said it is aware of 47 front-impact accidents associated with the ignition-switch failure, having earlier put that number at 32.

The ignition-switch problem has led to recalls of 2.6 million GM vehicles, and prompted federal fines and multiple investigations into why GM neglected to issue the recalls for more than a decade.

The company has said it is taking several hundred million dollars in write-downs related to the recalls.

GM may also face civil lawsuits and criminal charges.