Sweden and Finland formally apply to join NATO after Russia invaded Ukraine

The application by Sweden and Finland to join the North Atlantic Treaty Organization marks a massive shift in Europe's security landscape.

NATO Secretary General Jens Stoltenberg received applications from the ambassadors of Sweden and Finland to join the alliance on Wednesday morning.

NATO welcomed the applications from Sweden and Finland.

This is a historic moment, which we must seize, according to Stoltenberg.

I welcome the requests by Sweden and Finland to join NATO. Membership in NATO will increase our shared security because you are our closest partners.

Both countries, which were non-aligned throughout the Cold War and beyond, made their decisions after Russia invaded Ukraine. Sweden and Russia have a long border.

The expansion of NATO's eastern borders would anger Russian President Vladimir Putin and his officials, who have long complained about the alliance's eastward expansion.

If they joined NATO, Russia has threatened consequences against them.

Russian officials began to downplay the effect of the two nations joining NATO.

On Monday, Putin said that Russia wouldn't have a problem with these states joining the bloc.

Russia's Foreign Minister said on Tuesday that Sweden and Finland had been participating in NATO military exercises for a long time.

It could take several weeks or months for Sweden and Finland to join NATO.