On Sunday afternoon, President Sauli Niinistö and Prime Minister Sanna Marin (SDP) announced that Finland will seek to join the North Atlantic Treaty Organisation (Nato).
Niinistö formally made the announcement in Finnish, Swedish and English, saying that Finland was entering a new era.
"This is a historic day," said the head of state, noting that he had begun the day by visiting the graves of war dead on Finnish Memorial Day.
"These decisions will strengthen, not weaken, our security," said Marin.
According to a government statement, the president and the Ministerial Committee on Foreign and Security Policy finalised the report on Finland’s accession to Nato (siirryt toiseen palveluun) on Sunday morning. It will be submitted to Parliament once it has been endorsed by the full cabinet.
In the meeting, Niinistö and the Ministerial Committee agreed that Finland would apply for membership after Parliament has been heard. Under the constitution, Finland's foreign policy is led by the president in co-operation with the government. Entry into international obligations must be confirmed by Parliament.
Speaking later at the press conference at the Presidential Palace were Defence Minister Antti Kaikkonen (Cen) and Foreign Minister Pekka Haavisto (Green).
In a joint statement last Thursday, Niinistö and Marin said that Finland should apply for Nato membership as a matter of urgency.
The application, to be filed within the next two or three days, marks a dramatic shift in Finnish security policy, away from its traditional military non-alignment.
Finland and neighbouring Sweden have been "enhanced members" of Nato's Partnership for Peace programme since 2013 and regularly taken part in Nato-led operations and exercises.
Before the Russian attack on Ukraine, support for joining the alliance had long been lukewarm among the Finnish public and nearly all political parties. During this spring, public support rose from less than half to more than three quarters in Yle polls.
Parliament begins consideration of the issue on Monday morning.
After the open-ended debate and certain approval by the legislature, the president and government will put the application process into motion, possibly as soon as Tuesday. A parliamentary rubber stamp is assured, as nearly all parties have already approved the application.
Neighbouring Sweden is also to decide on its application within the next few days. The governing Social Democratic Party there is to announce its stance on Sunday evening.
In response to reporters' questions, Niinistö discussed his recent phone discussions with his Russian, Turkish and American counterparts.
He said that Saturday's call to Russian President Vladimir Putin was calm on both sides. According to Niinistö, Putin stated that in his view Finland was "not under any threat" and that joining Nato was "a mistake". He described Putin's reaction to the decision as surprisingly muted considering Putin's previous threats over Finnish moves toward membership.
Niinistö was also asked about Turkish President Recep Tayyip Erdogan's comment on Friday that allowing Finland and Sweden to join Nato would be "impossible" for Turkey to approve, due to the Nordic countries' alleged support for Kurdish separatists. All 30 Nato member states must approve any new members.
The Finnish president said he was confused by this statement. He referred to a call with Erdogan about a month ago, in which he said the latter had raised the issue of Nato, saying that Turkey would support a bid.
Niinistö said he was prepared to discuss any issues with Erdogan.
Haavisto said on Sunday that Finland's stance on the Kurdish militant group PKK was in line with that of the EU, which has classified it as a terrorist group.
He met on Saturday in Berlin with his Turkish counterpart Mevlut Cavusoglu, who suggested that Ankara would not necessarily block Finland and Sweden from joining Nato, but that it wanted to negotiate on the issue.
Niinistö, who spoke by phone with US President Joe Biden on Friday, said that Washington has offered support over recent months, but that Biden had explained that it could not offer binding security guarantees during the Nato application process without a separate Senate decision, which would be nearly unprecedented.
Marin said that Finland is well prepared for any possible Russian retaliation in response to the application.
"Finland is a nation of preparedness, as we have seen during the pandemic," she said, adding that "the decisions we're making this week will ensure that there will never again be a war in Finland."