Russia warned on Thursday it would take military action if Finland joined Nato after the Scandinavian country said it was in favor of joining the military alliance.

“Russia will be forced to take military-technical and other responsive measures in order to counter the threats that have emerged to its national security,” the foreign ministry said in a statement.

Russia’s warning came after Finland said on Thursday that it was in favor of applying to join the Nato alliance in a historic move that marks a huge geopolitical change.

“Finland must apply for Nato membership without delay. We hope that the national steps still needed to make this decision will be taken rapidly within the next few days,” Finnish president Sauli Niinisto and prime minister Sanna Marin said in a joint statement.