The admission of Finland and Sweden to NATO will be a grave mistake with far-reaching consequences, says Russian Deputy Foreign Minister Sergei Ryabkov.

Military tensions would increase as a result, Mr Ryabkov warned on Monday, according to the Interfax news agency.

Addressing the two Scandinavian countries, he added that “they should have no illusions that we will simply resign ourselves to this.”

In a telephone conversation with Finnish head of state Sauli Niinistö, President Vladimir Putin spoke of a mistake by Helsinki and insisted Russia posed no threat to Finland.

The two countries share a 1300-kilometre border.

Russia’s invasion of Ukraine strongly influences the plans for NATO membership.

Finland, which has been neutral for decades, plans to apply for membership in the North Atlantic Treaty Organisation, which currently has 30 members.

Traditionally non-aligned Sweden has also decided on a historic U-turn, with the governing Social Democrats now in favour of joining the Western military alliance.

The parliaments of both countries are to meet for debates on the issue on Monday.

(dpa/NAN)