WASHINGTON (Reuters) - The Pentagon and U.S. Navy on Friday ordered a temporary grounding of the Marine Corps version of Lockheed Martin Corp's F-35 fighter jet after an incident that occurred during a training flight at Eglin Air Force Base in Florida on Wednesday.

The Pentagon's F-35 program office said the grounding affected all 25 F-35B model jets, while flights of the Air Force's A-model and the Navy's C-model were unaffected. Ground operations of the B-model planes continued.

The program office said the grounding was ordered after a propulsion line associated with the B-model's exhaust system failed prior to takeoff. The pilot aborted the takeoff without incident and cleared the runway, the program office said in a statement. There were no injuries to the pilot or ground crew.

(Reporting By Andrea Shalal-Esa; Editing by Bernard Orr)