Production of the F-35 likely will be slowed down, according to Frank Kendall, undersecretary of defense for acquisition, technology and logistics,
Kendall said that while that the F-35 fighter jet is the Pentagon's "most cutting-edge capability," other priorities need to be funded as well.
"Dollar for dollar it probably gives us more combat capability than any other investment that we're making, but we've got a lot of other things that we need to do as well," he said. "It's not entirely fenced."
Kendall gave no details on the likely scope of the expected cuts in production of the F-35 fighter jet, which is already cleared for combat use by the Marine Corps.
Under the original contract with the F-35's manufacturer, Lockheed Martin, 1,013 of the program's 2,443 jets were supposed to be delivered by September 30, 2016. So far, only 179 have been delivered.
Senator John McCain, chairman of the Senate Armed Services Committee, on Wednesday said that to fulfill the contract, the Pentagon would have to purchase 100 F-35s per year for more than 20 years at a cost of $10 billion to $12 billion a year.
"I'm not saying we shouldn't have 2,443. I just want to know how you get there," McCain said. "If it's not a realistic estimate, shouldn't we have a realistic estimate?"
The F-35 program has suffered delays, technical glitches and massive cost overruns. It is now estimated to cost more than $391 billion to purchase all 2,443 jets, according to the Government Accountability Office.