The US is pushing for Switzerland to bear extra costs for producing the jets of between 650 million and 1.3 billion Swiss francs ($807 million-$1.6 billion), but the Swiss want to agree a fixed price.

The Swiss Federal Council said "intensive discussions" between the two countries had shown the US was "not prepared to deviate from its position" on a contract worth six billion Swiss francs, with its first deliveries due in 2027.

The council said the final price of the procurement would depend on factors including US inflation, commodity prices and US tariffs.

"The Federal Council remains committed to procuring the F-35A," the council said, insisting the jets had "significant technological advantage over other aircraft".

But the council said it had asked the defence department to review all the available options and report back by November.

Defence Minister Martin Pfister had earlier floated an idea to buy fewer than the 36 aircraft initially agreed.

He told journalists on Wednesday costs could also be kept down by bringing Swiss companies on board as subcontractors rather than using US firms, or by agreeing an additional budget with parliament.

The minister ruled out relaunching the whole process and reconsidering other types of aircraft, saying such a move would "take a long time and undoubtedly cost more".

The government won a referendum in September 2020 by a razor-thin margin that approved the military spending six billion Swiss francs on a new fleet.

The F-35A, used by the US Air Force and several European countries, was chosen in June 2021 over competitors from Airbus, Boeing and Dassault.

Switzerland's long-standing position has been one of well-armed military neutrality, and the country has mandatory conscription for men.

vog/jxb/dc

Airbus Group

BOEING

Dassault Aviation