DETROIT — General Motors on Friday said it is recalling more than 68,000 Chevrolet Bolt electric vehicles, a month after regulators began investigating whether they were at risk of catching fire.

GM said it has identified five Bolt fires — two more than NHTSA cited in opening a preliminary evaluation of the matter. The fires possibly relate to high-voltage batteries produced by LG Chem in South Korea, GM said.

The automaker and NHTSA are still working to determine the cause of the issue, but GM plans to have a remedy as soon as possible after the first of the year, Jesse Ortega, the Bolt’s executive chief engineer, told reporters.

In October, NHTSA said it had received two complaints claiming “the vehicles caught fire under the rear seat while parked and unattended.” NHTSA also found a 2017 Bolt with a similar pattern.

GM and NHTSA found two cases of smoke inhalation related to the fires but there are no other known injuries.

The recall covers Bolts from the 2017-19 model years. Of the 68,667 being recalled, 50,925 were sold in the U.S.

GM does not believe all recalled vehicles are affected. Bolts built for the 2017 and 2018 model years used the LG Chem batteries made in South Korea. For the 2019 model year, some Bolts were built with the Korean batteries, while others used LG Chem batteries made in Holland, Mich.

GM said 2020 Bolts are not affected because they were built with a different battery chemistry that increased range.

In each of the five confirmed cases, the batteries were at or near their maximum charge, Ortega said.

GM planned to notify dealers and customers of the recall Friday. The automaker is telling customers who have a 2017 or 2018 Bolt that they can drive using Hilltop Reserve mode until a software update is available. It is instructing owners of 2019 models to set their battery charge to a maximum of 90 percent. GM said it’s releasing a video Friday to show customers how to change the settings in their Bolt vehicles.

Once a fix is available, dealers should update new and used Bolts’ software before they are sold, GM said.