He said: “We have repeatedly said that the alliance remains a tool geared towards confrontation and its further expansion will not bring stability to the European continent.”

However, public support for joining the military alliance almost doubled in the two countries since the Russian invasion of Ukraine began in February.

Opinion polls suggest that around 50 percent of Swedes and 60 percent of Finns support joining NATO.

The Swedish government has started debating potential accession, while Finland is expected to reach a decision about membership within weeks.

On Sunday, it was reported that US officials are expecting Finland to apply for a membership as early as June, which would be followed by Sweden.

US officials told The Times that NATO membership for both nations was discussed in multiple conversations and sessions during meetings between the alliance’s foreign ministers last week.

Former Finnish Prime Minister Alexander Stubb said last week that Helsinki could make a bid to join as early as May.

Tobias Baudin, the secretary for Sweden’s ruling Social Democratic party, reportedly said it was considering its international security policy, and would discuss whether to join the alliance.

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He said: “If they decide to apply, I expect that all allies will welcome them. We know that they can easily join this alliance if they decide to apply.

“I am certain that we will find ways to address concerns they may have regarding the period between the potential application and the final ratification.”