NATO is an is an intergovernmental military alliance among 28 European countries and 2 North American countries. Established in the aftermath of World War II.

NATO constitutes a system of collective security, whereby its independent member states agree to mutual defense in response to an attack by any external party.

Sweden has since 1905 been at peace, maintaining an official policy of neutrality in foreign affairs. Sweden was formally neutral through both world wars and the Cold War, although Sweden has since 2009 openly moved towards cooperation with NATO.

France 24 reports

The Russian invasion of Ukraine has upended the status quo in traditionally non-aligned Finland and Sweden, ushering in an "historic" surge in support for NATO, "exceptional" arms exports and defiance to Moscow's demands.

Stockholm and Helsinki have ruled out applying to join the NATO military alliance for the time being but the two countries have never been so close to taking the plunge, analysts say.

"Anything is possible at the moment and the signal from NATO countries is that a membership application can be processed in a very short time-span," said Zebulon Carlander, defence analyst with the Society and Defence organisation in Sweden.