Prime Minister Sanna Marin of Finland has said that her nation will make a decision on NATO membership within weeks.

At a joint press conference with Sweden’s prime minister, she said she saw no need to delay the decision.

She made these remarks at the same time as a study presented to the Finnish parliament warning that participation in the union may lead to “greater tensions on the border between Finland and Russia.”

In recent weeks, Moscow has sent warnings to Finland and Sweden against joining NATO.

Since Russia’s invasion of Ukraine, popular support in Finland and Sweden has grown for joining the Western defence alliance. Magdalena Andersson, Sweden’s leader, told reporters that her country was doing the same “extremely serious study” as Finland and that she saw no purpose in prolonging it.

According to the Swedish daily Svenska Dagbladet, Ms Andersson plans to submit an application for NATO membership by the end of June, just in time for the summit.

There is a 1,340-kilometer border between Finland and Russia, and Kremlin spokesperson Dmitry Peskov has highlighted that Moscow would have to “rebalance the situation” with its own measures if NATO membership was granted.

“I won’t provide any type of schedule when we will make our judgments, but I think it will happen very quickly,” added Ms Marin. She reminded out that NATO membership provided Finland with the security assurance of Article Five, in which an assault on one state is seen as an attack on all members.

While the two presidents met in Stockholm, Finland started its security review in Helsinki. There is a need to rethink Finland’s defence strategy, says Foreign Minister Pekka Haavisto, because of the battle between Russia and Ukraine.

Because of Russia’s invasion of Ukraine, European security is in jeopardy. NATO’s military alliance has a new mission, and new countries might join it soon.

The non-alignment status of Finland and Sweden has long been prized by voters. However, things have changed. A “foregone conclusion” has been predicted by Sanna Marin’s former Prime Minister, Alexander Stubb.

The ruling Social Democrats in Sweden are re-evaluating their long-standing opposition to Sweden joining NATO.

However, Russian officials have stated time and time again that any extension of NATO would be deemed a “provocation” and that there would be “consequences”.