Russian President Vladimir Putin cautioned his Finnish colleague on Saturday that Finland’s ambitions to qualify for NATO membership could “harm” relations between the two countries.

According to the Kremlin’s press office, Putin informed Sauli Niinisto that abandoning Finland’s “traditional policy of military neutrality would be an error because there are no threats to Finland’s security.”

“Such a change in the country’s foreign policy could negatively affect Russian-Finnish relations, which had been built in the spirit of good neighborliness and partnership for many years, and were mutually beneficial,” the statement added.

The response came after Niinisto told Putin in a phone conversation that the militarily non-aligned Nordic country that has a complex history with its huge eastern neighbor “will decide to apply for NATO membership in the coming days”.

Niinisto’s office said in a statement that the Finnish head of state told Putin how starkly Finland’s security environment had changed after Moscow’s Feb. 24 invasion on Ukraine, and pointed to Russia’s demands on Finland refraining from seeking membership to the 30 member-state Western military alliance.

“The discussion (with Putin) was straightforward and unambiguous and was held without exaggeration. Avoiding tensions was considered important,” said Niinisto, Finland’s president since 2012 and one of a handful of Western leaders who has been in regular dialogue with Putin over the past decade.

Niinisto pointed out that he had already told Putin at their first meeting in 2012 that “each independent nation would maximize its own security.”