While the planes won't be in service for a few years - non-NATO Finland earlier stated 2027 - the agreement indicates the country's growing collaboration with the Western military alliance, as well as how its defence forces materiel policy is focused on all new equipment being NATO-compatible.

Finland's government stated that the decision to purchase the US jets, announced in December, was part of long-term preparations to strengthen the country's defences, rather than a reaction to the ongoing conflict between the West and Russia over Ukraine.

"It is part of our long-term strategy and has nothing to do with the current situation," Finland's ambassador to the United States, Mikko Hautala, said.

Finland's Prime Minister, Sanna Marin, stated in January that the government has no plans to apply for NATO membership at this time, but that his country retains the freedom to do so.

In addition to the F-35s, Defence Minister Antti Kaikkonen decided on Friday that Finland would purchase surface-to-surface missiles from Lockheed for 75 million euros in order to improve the performance and range of its heavy rocket launcher system, according to a statement from the Defence Ministry.

It is expected that munition deliveries will commence in 2025. Surface-to-surface missiles with a range of more than 135 kilometres could be deployed offensively or as deterrence against ground invasion.