WASHINGTON — An F-35A caught fire during an exercise at Mountain Home Air Force Base, Idaho, the Air Force confirmed to Defense News.

The incident took place at around noon and involved an F-35A aircraft from the 61st Fighter Squadron located at Luke Air Force Base, the service said in a statement. No serious injuries seem to have been sustained by the pilot or nearby crew.

"The pilot had to egress the aircraft during engine start due to a fire from the aft section of the aircraft," Air Force spokesman Capt. Mark Graff said in an email. "The fire was extinguished quickly. As a precautionary measure, four 61st Aircraft Maintenance Unit Airmen, three Airmen from the 366th Maintenance Group and the 61st Fighter Squadron pilot were transported to the base medical center for standard evaluation." 

Seven F-35As from Luke AFB, which is one of the bases responsible for joint strike fighter pilot instruction, had deployed to Mountain Home to conduct surface-to-air training from Sept. 10 to 24. 

The root cause of the event is under investigation, Graff stated. 

At the time of publication, it is still unknown whether the fire originated from the F-35's F135 engine, manufactured by Pratt & Whitney.

"We are aware of an incident involving an F-35A jet from Luke Air Force Base operating at Mountain Home Air Force Base, but we do not have any further details at this time," said Pratt & Whitney spokesman Matthew Bates. "We are ready to assist the U.S. Air Force and the F-35 Joint Program Office in their investigation."

It's also unknown if there is a connection to a recent problem with the F-35A's coolant line insulation that caused the flight operations of 15 joint strike fighters to be suspended. During depot maintenance it was discovered that the insulation around the coolant lines was breaking down inside the fuel tank— a situation the joint program office said was due to the supplier using the incorrect materials to manufacture the insulation.

The insulation issue also impacts 42 F-35s on manufacturer Lockheed Martin's production line. When the problem was made public last Friday, JPO officials said they were certain no other planes had been affected. Earlier this week, F-35 Joint Program Executive Officer Lt. Gen. Christopher Bogdan said Lockheed planned to test a potential fix next week, and if it works, company teams would roll out the following week to begin repairs. 

Marine Corps Times Reporter Jeff Schogol and Defense News reporter Aaron Mehta contributed to this report.