Finland and Sweden are also not yet members of the alliance. However, since Russia began its invasion of Ukraine more than a week ago, public support in the two Scandinavian countries to join NATO has rocketed.

For the first time ever, the majority of Swedes support NATO membership, according to a poll by newspaper Aftonbladet – 51 percent of the public is now in favour of joining.

Meanwhile, a survey in Finland identified this week that 53 percent of Finns supported joining NATO. The number went up to 66 percent if Sweden were to join too.

While NATO membership remains open to them, Finnish and Swedish leaders have not called for their countries to join the military alliance.