Finnish President Sauli Niinisto said that Finland joining NATO "would not be against anyone," despite Russia's warning against the membership. The Finnish President's words came during the signing of a political declaration of mutual assistance with the UK Prime Minister Boris Johnson, today, Wednesday.

"Joining NATO would not be against anyone. It is not a zero-sum game," he said.

The Nordic country's President said if joining the alliance happens, his response to Russia would be "you caused this, look in the mirror."

The declaration notes that should Finland "suffer a disaster or an attack," the United Kingdom will help in a variety of ways "which may include military means."

"Finland is already an enhanced partner in NATO. There is no doubt in anybody’s mind that Finland is part of the West," Niinisto said.

He noted that it is a different situation now, as Moscow had previously considered that militarily non-aligned Finland and Sweden were "stabilizing" the Baltic region.

"But then, in the end of last year, they stated that Finland and Sweden can’t join NATO. They demanded that NATO doesn’t take new members. Russia actually expressed that you don’t have your own will", the President said, adding this was a "huge change".

Russia's operation in Ukraine amid the eastward expansion of NATO forces on Russia's borders has resulted in a dramatic turnaround in Finnish political and public opinion in favor of joining the alliance.

Finland leaders will announce on Thursday their positions on whether they will be joining NATO.