The top U.S. auto safety regulator stated on Monday it will start an investigation into 3 million Hyundai Motor and Kia Motors vehicles after reviewing reports of more than 3,000 fires that injured more than 100 people.
The National Highway Traffic Safety Administration (NHTSA) stated the probe is in response to a petition seeking a probe submitted in June by the Center for Auto Safety.
The investigation concerns the 2011-2014 Kia Optima and Sorento and the 2010-2015 Kia Soul, together with the 2011-2014 Hyundai Sonata and Santa Fe.
The investigation rekindles safety issues about vehicles of the South Korean duo, who have already been probed by the U.S. regulator and prosecutors over engine-related recalls.
Hyundai and Kia together have recalled more than 2.3 million vehicles since 2015 to address different engine fire risks.
Hyundai stated that it was cooperating and added it has been frequent, open and transparent dialogue about non-collision engine fires.
Kia said it will keep working with NHTSA and openly shares the data with NHTSA on all matters pertaining to auto safety.