Kia is recalling about 65,000 vehicles in Canada and more than 507,000 in the United States because an electronic glitch may prevent airbags from deploying in the event of a crash.
Another major automaker is recalling vehicles due to air bag issues.
The agency said would evaluate the Hyundai-Kia problems and will investigate whether any other vehicle manufacturers used the same or similar ZF-TRW air bag computers.
Vehicles covered by the recall include 2010 through 2013 Forte compact cars and 2011 through 2013 Optima midsize cars.
In the affected vehicles, the air bag control unit may short circuit and prevent the front air bags and seat belt pretensioners from deploying in a crash, according to the NHTSA recall notice.
"Kia is now evaluating a remedy for this recall".
A Hyundai spokesman says he's checking to see if his company has a recall.
"NHTSA's investigation should not have even been necessary", said David Friedman, director of cars and product policy and analysis at Consumers Union, the advocacy division of Consumer Reports. Those include the 2011 through 2013 Sonata midsize vehicle and the 2011 and 2012 Sonata Hybrid.
The Kia Sedona will have to head back as NHTSA reports that there is an issue with the sliding doors that might cause injuries to the driver or passenger. The company provided technical support to Kia, it said. The parts supplier issued a statement saying it's cooperating with the government's investigation, The Associated Press reported. The agency also said it's investigating whether the automakers followed safety reporting requirements.