Sweden and Finland will be fast-tracked into Nato after they submit a joint application to join, an analyst has told The National.
The two countries will submit applications to join Nato in May, media reports suggest.
Sweden suggested the two countries should indicate their willingness to join on the same day and Finland agreed “as long as the Swedish government has made its decision”, according to Finnish daily newspaper Iltalehti.
Sweden's Expressen newspaper said government sources it spoke to had confirmed the decision.
Ben Barry, senior fellow for land warfare at the International Institute for Strategic Studies think tank, told The National political opinion in both countries had shifted in favour of Nato membership and their applications will be fast-tracked.
“It’s very simple: Nato is going to welcome this and Russia is going to regret it,” he said.
Any agreement would have to include a security guarantee during the transition period between applications and acceptance when Russia could “create mischief”, Mr Barry said.
Finland shares a 1300-kilometre border with Russia. They have a troubled history as Russia invaded Finland in 1939, starting the months-long Winter War that ended in the spring of 1940 with Helsinki ceding territory to Moscow.
Finland was neutral during the Cold War.
Russia’s illegal invasion of Ukraine has proved decisive in pushing Sweden and Finland towards Nato.
Swedish Prime Minister Magdelena Andersson and Sanna Marin, her Finnish counterpart, have accepted that events have changed the security landscape of Europe.
The shift in Finland away from neutrality is particularly marked, with 68 per cent of public opinion in favour of Nato membership — double the figure in polls before Russia invaded Ukraine in February.
Polls in Sweden have shown small majorities in favour of joining the alliance.
Despite concerns about angering Moscow, Mr Marin said her country would join Nato “in weeks, not months”.
Ms Andersson said Sweden had to be “prepared for all kinds of actions from Russia”.
Moscow said it was prepared to station nuclear arms in its exclave of Kaliningrad, which borders Poland and Lithuania.
Mr Barry said he believed that nuclear weapons are probably already there and “Russia's main effort right now is Ukraine, so setting up a provocation in Scandinavia is not a high priority for them, but you never know.”
Last week, Swedish Foreign Minister Ann Linde said publication of her country's security review has been brought forward from May 31 to May 13.
Sweden and Finland could make their applications to Nato in the third week of May, media reports said.