U.S. safety regulators said on Friday they have opened an investigation into an estimated 50,415 newer Jeep Cherokee SUVs, a key model for the profitability of Fiat Chrysler Automobiles, after receiving complaints of engine compartment fires, reported Reuters.

The U.S. National Highway Traffic Safety Administration said it opened the preliminary evaluation into the 2015-model SUVs after a consumer from the San Diego area filed a complaint that their Jeep was "engulfed in flames approximately 20 feet high within seconds of parking the vehicle." There were no injuries reported.

The vehicle was purchased on Jan. 2 and the fire occurred two days later after the SUV had been driven less than 100 miles, according to the complaint filed by the consumer.

In another complaint filed on Jan. 5, the owner of a 2015 Cherokee noticed smoke under the hood while driving the newly purchased vehicle at 60 miles per hour.

In addition, NHTSA said it has identified field report data as part of the Early Warning Reporting program related to the alleged defect, so it opened the investigation to assess cause, scope and frequency of the alleged defect.

"We are aware of this incident and our investigators are cooperating fully with NHTSA's preliminary evaluation," Fiat Chrysler spokesman Eric Mayne said.

A preliminary investigation is the first step in a process that can lead to a recall if regulators determine that a manufacturer needs to address a safety issue.

The Cherokee, a new version of which was launched in 2013, is a critical part of Fiat Chrysler's plan to boost profits globally by leveraging its Jeep brand.

NHTSA and Fiat Chrysler have disagreed before about fire risks in older Jeep SUVs. In November, the safety agency urged the automaker to speed up efforts to fix 1.56 million Jeep SUVs at risk of gas tank fires in a rear-end collision.

Fiat Chrysler, which had initially resisted the recall, stepped up its efforts, but has long maintained the SUVs were no more susceptible to fires after crashes than vehicles made by other automakers.

Fiat Chrysler Chief Executive Officer Sergio Marchionne said this week at the Detroit auto show that the auto industry has become more sensitive about recalls and if the trend continued the higher cost of recalls would be passed on to consumers.