The war in Ukraine has prompted Finland's historic accession to NATO, which has angered Russian authorities, who view the move as dangerous.
The Finnish flag was raised at the headquarters of the world's largest military alliance in Brussels on Tuesday afternoon, nearly a year after Helsinki formally requested membership.
Earlier, Finnish Foreign Minister Pekka Haavisto concluded the admission process by delivering an official paper to US Secretary of State Antony Blinken; the United States Department of State is the custodian for NATO membership documents.
North Atlantic Treaty Organization (NATO) chief Jens Stoltenberg praised "a good day for Finland's security, Nordic security, and NATO as a whole."
He stated, "This will make Finland safer and NATO stronger." This is the quickest NATO admission process in history.
Sauli Vainamo Niinisto, president of Finland, stated that membership was not "targeted against anyone" and that his nation was "stable and predictable."
Fears of Russian aggression grew in northern Europe after Moscow invaded Ukraine, prompting Finland and Sweden to submit applications in May.
Niinisto stated, "Finland's membership is incomplete without Sweden." "I'm looking forward to Sweden becoming our 32nd member."
The reservations of NATO members Turkey and Hungary prevent Sweden, which has shunned military alliances for almost two centuries, from joining NATO.
Political Blow to Putin
The length of Finland's border with Russia is 1,340 kilometres (833 miles).
In response to Finland's membership, Russia has long maintained that NATO expansion threatens its security and has pledged to increase its military power in its western and northern territories.
Authorities in Russia, including President Vladimir Putin, assert that the deployment of armed forces into Ukraine in February 2022 was, in part, a response to suspected Western plans to use Ukraine as a launching pad to attack Russia.
They assert they are engaged in a "hybrid war" against NATO and the West, providing Ukraine with multibillion-dollar arms and financial support packages.
Before accepting the documents, Blinken stated, "I'm tempted to say that this is perhaps the only thing for which we can thank Putin."
Teivo Teivainen, a professor of international relations at the University of Helsinki, told Al Jazeera, "The majority of Finns believe they are safe under NATO's Article 5."
Article 5 stipulates that if one NATO member is attacked, the other alliance members must consider it an act of aggression.
Teivainen stated that the new membership "increases Finland's security."
The doubling of Russia's border with NATO countries due to Finland's accession to the alliance represents a significant shift in Europe's security picture.
After its defeat by the Soviet Union in World War II, Finland adopted a neutral stance.
Nevertheless, months after Putin's invasion of Ukraine shook Moscow's neighbours with alarm, Finland's authorities signalled their desire to join the alliance.
The action is a strategic and political blow to Putin, but according to the alliance, it poses no threat to Moscow.
According to a transcript issued by his ministry, Russian Defense Minister Sergei Shoigu told Russia's military command in a meeting on Tuesday that Finland's entry "creates the risk of a significant expansion of the conflict" in Ukraine.
Nonetheless, he stated that the outcome of Russia's "special military operation" in Ukraine would not be affected.
