Ford and Mazda on Tuesday issued “do not drive” warnings to owners of more than 457,000 older vehicles across the United States due to a severe safety threat posed by defective Takata air bag inflators.

According to the National Highway Traffic Safety Administration (NHTSA), which announced the car manufacturers warning, the warning affects all unrepaired, recalled Ford, Lincoln and Mercury vehicles, as well as all Mazda vehicles that are equipped with unrepaired Takata air bags. The advisories cover more than 374,000 vehicles from Ford spanning model years from 2004 through 2014 and nearly 83,000 Mazda vehicles from 2003 through 2015 model years.

Consumers are urged to not drive the vehicles until repairs are made on the air bags.