June 13, 2018—A consumer watchdog group is pressing the National Highway Traffic Safety Administration to investigate complaints of spontaneous fires, unrelated to crashes, in certain Kia and Hyundai vehicles, according to Consumer Reports.

The Center for Auto Safety (CAS) filed a formal petition with NHTSA on Tuesday. In it, the center pointed to an unusual number of consumer complaints about four models, all from model years 2011 to 2014: the Kia Optima sedan and Sorento SUV, and the Hyundai Sonata sedan and Santa Fe SUV.

At least six people have been injured in the incidents, the center said.

The center found 120 complaints in the NHTSA database where consumers reported fires without a preceding collision. There were also 229 separate complaints of melted wires in the engine bays, smoke, or burning odors indicating potential fires, the center said. NHTSA should focus on instances where wiring harnesses interact with fender edges, it said.

Hyundai told Consumer Reports it's aware of the Center for Auto Safety petition and is reviewing it. It noted the number of reported fires in the subject vehicles is "extremely low."