WASHINGTON (Reuters) - The Pentagon on Friday suspended the flights of all F-35 fighter planes after a routine inspection revealed a crack on a turbine blade in the jet engine of an F-35 test aircraft in California.

The F-35 program office said it was too early to know the fleet-wide impact of the engine issue, but it was suspending all flights until an investigation into the issue was completed.

It said it was working closely with Pratt & Whitney, the United Technologies Corp unit which builds the engine for the fighter, and Lockheed Martin Corp, the prime contractor for the radar-evading warplane, to ensure the integrity of the engine and return the F-35 fleet to flight as soon as possible.

(Reporting By Andrea Shalal-Esa; Editing by Gerald E. McCormick)