Finland’s president and prime minister have announced that the Nordic country intends to apply for membership in NATO, paving the way for the 30-member military alliance to expand amid Russia’s invasion of Ukraine.

President Sauli Niinisto and Prime Minister Sanna Marin made the announcement at a joint news conference at the Presidential Palace in Helsinki on May 15.

“Today, the president of the republic and the government’s Foreign Policy Committee have jointly agreed that Finland will apply for NATO membership, after consulting parliament. This is a historic day. A new era is opening,” they said.

Last week, the president and prime minister said they both favored NATO membership, in a major policy shift prompted by the war in Ukraine.

Finland shares a 1,300-kilometer border with Russia and has remained militarily nonaligned for 75 years.

But after Russia invaded Ukraine in February, political and public opinion swung dramatically in favor of membership.

Russia has said it would be a mistake for Helsinki to join the transatlantic alliance and that it would harm bilateral ties.

Earlier this week, Niinisto told reporters that “joining NATO would not be against anyone.”

He said his response to Russia would be: “You caused this. Look in the mirror.”

The Finnish parliament is expected to endorse the decision in the coming days, but it is considered a formality.

The announcement comes as top NATO diplomats are meeting in Berlin on May 15 to discuss providing further support to Ukraine and moves by Finland, Sweden, and others to join the alliance.