Russian Deputy Foreign Minister Sergei Ryabkov on Monday said Finland and Sweden should have no illusions that Moscow will simply put up with their joining the NATO military alliance, calling it a mistake that would have far-reaching consequences.

The move from two historically neutral powers would be one of the biggest changes to Europe’s security architecture for decades, reflecting a sweeping shift in perceptions in the Nordic region since Russia sent tens of thousands of troops into Ukraine on Feb. 24.

“The situation is, of course, changing radically in light of what is happening,” the Interfax news agency quoted Ryabkov as saying. “The fact that the security of Sweden and Finland will not be strengthened as a result of this decision is very clear to us.

“They should have no illusions that we will simply put up with it,” Ryabkov said.

“The general level of military tension will rise, and predictability in this sphere will decrease. It is a shame that common sense is being sacrificed to some phantom provision about what should be done in this unfolding situation,” Ryabkov said.

The move by the two historically neutral countries marks one of the biggest changes to Europe’s security architecture in decades, following Russia’s invasion of Ukraine on February 24.

NATO expansion to Finland and Sweden could have an impact on the conflict in Ukraine, a development that allows the West to further strengthen its position against the expansionist aspirations of Vladimir Putin, after the historic decision of the Nordic countries to dramatically change security policy.

This is Moscow’s first major defeat since the start of the Russian invasion of Ukraine, at a time when clashes on the Donbas front and control of the Black Sea have not yet yielded the desired results for Putin and the danger of a prolonging of the war becomes more and more real.

The Kremlin’s threats against Helsinki and Stockholm fell on deaf ears and failed to achieve its goal of maintaining the two countries’ neutrality for decades.