The former Deputy Secretary General of NATO has told Forces News she believes Finland and Sweden's applications to join NATO are a "strategic defeat" for Russia.
"It's turning the Baltic Sea into a NATO lake, essentially," Rose Gottemoeller said.
If Finland and Sweden were to formally join the alliance, the border NATO has with Russia would double in length.
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"For my thinking, this is exactly the opposite of what Vladimir Putin seemed to want when he invaded Ukraine," she added.
Both Sweden and Finland have previously opted to stay neutral and keep out of NATO, but public sentiment for joining the alliance has grown following Russia's invasion of Ukraine.
However, Ms Gottemoeller said she does not think the concept of neutrality is going away.
"We have a number of good NATO partners in Europe... who have been good NATO partners and these countries I don't necessarily see as coming closer to NATO in a way that would threaten their neutrality stance."
Earlier this week, NATO Secretary General Jens Stoltenberg said that Sweden and Finland's applications to join will be fast-tracked.