SALZBURG, Austria — Finland and Sweden need to join the North Atlantic Treaty Organization (NATO) now while Russia’s Putin is focused on Ukraine, the alliance’s former chief told CNBC.

The two Nordic countries have been considering joining NATOFollowing the success of Russia’s unprovoked invasion of Ukraine. After years of being neutral, becoming NATO members would be a major change in the way they view Moscow. In the next few days, Sweden and Finland will announce their plans.

“I believe there is a window for opportunity in Finland and Sweden, as far as Finland or Sweden are concerned.” [the]Two countries will join NATO, but only now as Putin is busy elsewhere. Anders Rasmussen (ex-NATO secretary general), said Saturday that he couldn’t make any changes.

Russia repeatedly declared its opposition to NATO’s expansion and has called this one of the main reasons it invaded Ukraine. 

The Kremlin also stated that if Stockholm or Helsinki joined the alliance it would need to “rebalance” the situation.

If both countries move forward with their memberships, it is not clear how the Kremlin will react.

But, they would be able to double the NATO-Russia border as well as significantly increase the military power of the alliance.

NATO Secretary General Jens Stoltenberg previously stated that both countries would be welcomed.

Rasmussen said that it might take several months before the memberships become formal.

He said, “Even though it’s urgent, which it is), it will take some time because it must go through 30 parliaments before it can ratified across NATO.”

NATO is currently composed of 30 countries, with the United States as one of them.

Rasmussen explained that “it will take some time and both Finland or Sweden could possibly be exposed to Russian intimidation, threats, or even death, and that that’s why they have to ensure their security,” “as though they were already NATO members.”

These security guarantees would have to come from individual members of NATO as the alliance’s famous Article 5 — which states that an attack on one NATO member is an attack against all — would only apply to Finland and Sweden once their applications were ratified by all the 30 NATO members.

Unprovoked Russia’s invasion of Ukraine caused a change in Europe’s defense policies. Countries have announced a lot more spending on their military capabilities, have sent weapons to Ukraine and — in the case of Finland and Sweden — it has led to more public support for joining NATO.

You should be able to understand both the Swedish language and Finnish. [potential]This was an indication that Russia does not have any neutral borders. This is a new fact, even during Cold War it wasn’t like that,” Ivan Krastev (a political analyst) told CNBC Friday.

“Before [Russia’s invasion of Ukraine]There was confusion about the differences between NATO members and friends of the United States. It is now clear that NATO membership means Article Five. Being friends with the United States doesn’t. He said that Finland and Sweden should be considered members of NATO, rather than friends.