​Finland and Sweden are poised to join NATO as early as this summer, a move that a US official said stemmed from Russia’s “massive strategic blunder” of invading Ukraine, according to a report published Monday. ​​

Membership of the two Nordic countries in the Atlantic alliance was a “topic of conversation and multiple sessions” last week during meetings of NATO foreign ministers that were attended by representatives from Stockholm and Helsinki, the Times of London reported. 

Finland is expected to submit an application in June, with Sweden following soon after, the report said. 

The addition of Sweden and Finland would increase the alliance membership to 32 countries — and extend its border with Russia by hundreds of miles.

​​​“How can this be anything but a massive strategic blunder for [Russian President Vladimir] Putin?”​ a​ senior American official ​told the publication.

“Sweden and Finland would be real feathers in ​NATO’s cap as net contributors. They are real players,” a European diplomat ​told the Times, noting that adding both countries would help expand the alliance’s capabilities, including in intelligence gathering and in air power.

NATO Secretary General Jens Stoltenberg said that Vladimir Putin's invasion of Ukraine has created "a new reality, a new normal for European security."NATO Secretary-General Jens Stoltenberg said that Vladimir Putin’s invasion of Ukraine has created “a new reality, a new normal for European security.”EPA/STEPHANIE LECOCQ

Finnish Prime Minister Sanna Marin said it was time for her country to reconsider becoming a NATO member and urged the alliance to consider any potential application “thoroughly but quickly.”

“Russia is not the neighbor we thought it was,” ​Marin said earlier this month, adding: “I think we will have very careful discussions, but we are also not taking any more time than we have to in this process, because the situation is, of course, very severe​.”

Stockholm is following Helsinki’s timetable and is conducting a security policy review that is expected to be concluded by the end of May. ​

Finish Prime Minister Sanna Mirella Marin (left) has said that it was time for her country to reconsider becoming a NATO member and urged them to consider the application quickly but throughly.Finnish Prime Minister Sanna Mirella Marin (right) has said it was time for her country to reconsider becoming a NATO member and urged the alliance to consider the application quickly but thoroughly.Thierry Monasse/Getty Images

“I do not exclude N​ATO membership in any way,” ​Swedish Prime Minister ​Magdalena Andersson​ said in late March.

The Kremlin lashed out at Finland and Sweden on Monday in response to the report.

“We have repeatedly said that the alliance remains a tool geared towards confrontation and its further expansion will not bring stability to the European continent,” Moscow mouthpiece Dmitry Peskov told reporters.

Swedish Prime Minister Eva Magdalena Andersson has said that she does not expect a membership in any way. Swedish Prime Minister Eva Magdalena Andersson has said she does not expect a membership in any way. Thierry Monasse/Getty Images

F​inland, which shares an 830-mile border with Russia, has been rattled by the invasion of Ukraine and recently increased its defensive posture along the frontier.

Breaking with its long tradition of neutrality between Russia and the West, Finland also said at the end of February that it would supply Ukraine with military weapons. 

Public opinion in Finland has swung in favor of joining NATO since Russia invaded Ukraine Feb. 24, with polls showing 62% of Finns want to be part of the alliance as of mid-March, up from 53% in February

Finnish Prime Minister Sanna Marin (Right) and her Swedish counterpart Magdalena Andersson (left) speak to the media, outside the Prime Minister's official residence Kesaeranta in Helsinki, Finland, on March 5, 2022.Finnish Prime Minister Sanna Marin (right) and her Swedish counterpart, Magdalena Andersson, speak to the media outside the prime minister’s official residence, Kesaeranta, in Helsinki, Finland, on March 5, 2022.RONI REKOMAA/Lehtikuva/AFP via Getty Images

NATO Secretary-General Jens Stoltenberg said over the weekend that Putin’s invasion of Ukraine has created “a new reality, a new normal for European security” and announced the alliance is planning on stationing a permanent military force on member nations’ borders to ​prevent further Russian territorial ambitions.