The US military suspended all test flights Friday for the new F-35 fighter jet over potential engine problems, officials said, the latest setback for a program dogged by cost overruns and technical glitches.

The move was described as a "precautionary measure" after a crack was discovered on a turbine blade in one F-35 engine at Edwards Air Force Base in California.

"It is too early to know the fleet-wide impact of this finding, however as a precautionary measure, all F-35 flight operations have been suspended until the investigation is complete and the cause of the blade crack is fully understood," program spokeswoman Kyra Hawn said in a statement.

The suspension applies to all 51 jets in the F-35 fleet.

"We have to find out if this is an isolated incident or if it has design implications," Hawn told AFP.

The cracked turbine blade was being shipped to manufacturer Pratt and Whitney's engine plant in Middletown, Connecticut for an evaluation.

The Pentagon has high hopes for the radar-evading F-35 fighter, which is supposed to replace most of the combat aircraft fleet of the US Air Force, Navy and Marine Corps by the end of the decade.

The US military plans to produce 2,443 aircraft for the American military and several hundred others for eight international partners who have invested in the project, as well as at least two customers, Japan and Israel.

But countries taking part in the program are anxious about spiraling costs and incessant production delays, with some postponing or cutting investments.