Raytheon, the fifth-largest arms firm in the world, said Glenrothes will continue to be an important site in its UK operations for the foreseeable future.
The electronics systems it produces are some of the most advanced in the world especially in silicon carbide technology, which is revolutionising semiconductors by allowing power electronics to run more efficiently.
Raytheon is one of the Glenrothes area’s biggest private-sector employers as the workplace for almost 600 people.
The Fife town has been the US-owned weapons manufacturer’s sole UK production site for advanced electronics for 18 months.
Its history with the company stretches 50 years, and UK production was concentrated on it to improve efficiency.
Elsewhere in the UK, Broughton is Raytheon’s site for systems integration work, in particular for the Astor (Airborne Stand-Off Reconnaissance) programme.
Harlow and Waddington are design-and-build facilities for air traffic management, identification and jam-resistant navigation systems.
Raytheon also opened a £3 million cyber centre near Britain’s intelligence-gathering centre GCHQ in Cheltenham.
Raytheon UK generate about £400m a year and last year won a £95m contract with Israel to make Tamar missiles for its Iron Dome defence system, which stops rockets fired from Gaza.
The UK Government lifted restrictions on arms sales to Israel following a review of export licences for arms which may have been used in the bombing of Gaza.
A Raytheon spokesman said: “Glenrothes is important to us and will continue to be for the foreseeable future.”