Hyundai and Kia are recalling more than a half million vehicles in the U.S. due to new problems that can cause engine fires.

Documents posted Thursday by the government show the Korean automakers are adding three recalls after reports of fires across the nation.

The largest recall covers nearly 379,000 Kia Soul SUVs from 2012 through 2016 with 1.6-liter engines. Documents show that high exhaust gas temperatures can damage the catalytic converters. That can cause abnormal combustion and damage pistons and connecting rods. A failed connecting rod can pierce the engine block and cause oil leaks that can cause fires.

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In addition, Hyundai and Kia are recalling:

152,000 Hyundai Tucson SUVs from 2011 to 2013 and Kia Sportage SUVs from 2011 and 2012 to fix an engine oil pan leak that also can cause fires

U.S. safety regulators have been investigating Hyundai and Kia engine failures since May of 2016. Investigators also are looking at engine fires. Hyundai and Kia started recalling vehicles for engine failures back in 2015.