Finland and Sweden are poised to end decades of neutrality by joining the North Atlantic Treaty Organization (NATO). 

The two Nordic nations had long kept the military alliance at an arm's length, but Moscow’s so-called “special military operation in Ukraine” has reportedly sparked renewed security concern across the region, and the leaders of each country have signaled their desire to join the bloc after more than 75 years of military non-alignment, according to CNN.

Finnish leaders announced their intentions to join NATO on Thursday, and formally presented that desire at a press conference on Sunday.

Sweden's Prime Minister Magdalena Andersson followed suit on Monday, confirming her government had decided to begin the process of seeking NATO membership.

Meanwhile, China Global Television Network (CGTN) reports that Russian leader Vladimir Putin warned the West on Monday that Russia would respond if NATO began to bolster the military infrastructure of Sweden and Finland. 

Speaking at a summit marking Collective Security Treaty Organization's (CSTO) 30th anniversary in Moscow, Putin said Russia had no problem with Finland or Sweden, so there was no direct threat from NATO's enlargement, including those countries.

"But the expansion of military infrastructure into this territory would certainly provoke our response," Putin told the leaders of the organization, which includes Belarus, Armenia, Kazakhstan, Kyrgyzstan and Tajikistan.

"What that (response) will be - we will see what threats are created for us," said Putin. "Problems are being created for no reason at all.  We shall react accordingly."