STOCKHOLM/HELSINKI (REUTERS, BLOOMBERG) - Sweden and Finland are starting to win assurances of help if threatened by Russia in the interim period between an expected application to join defence alliance Nato and an eventual entry under the bloc’s collective security umbrella.

Sweden and neighbour Finland stayed out of Nato during the Cold War, but Russia’s annexation of Crimea in 2014 and its invasion of Ukraine have led the countries to rethink their security policies, with Nato membership looking increasingly likely.

Both countries are concerned they would be vulnerable during an application process, which could take up to a year to be approved by all Nato’s members.

“Naturally, I’m not going to go into any details, but I feel very sure that now we have an American assurance,” Swedish Foreign Minister Ann Linde told Swedish TV from Washington on Wednesday (May 4) after meeting US Secretary of State Antony Blinken.

“However, not concrete security guarantees, those you can only get if you are a full member of Nato,” she added.

Ms Linde declined to say what assurances she had received from Blinken.

“They would mean that Russia can be clear that if they direct any kind of negative activities against Sweden, which they have threatened, it would not be something that the US would just allow to happen ... without a response,” she said.

A US State Department statement issued after the meeting said Mr Blinken had reaffirmed Washington’s commitment to Nato’s policy of welcoming new members, but it made no mention of security assurances.

Also on Wednesday British Defence Secretary Ben Wallace told reporters in Finland that “it’s inconceivable that Britain would not come to the support of Finland or Sweden if it was ever attacked”, regardless of what stage of the Nato entry process they are at, according to multiple media.

The “best security guarantee” would be to “keep the ratification process as short as possible”, Finnish Prime Minister Sanna Marin told reporters in Copenhagen on Wednesday, referring to the 30 parliaments in Nato countries that have to sign off on any new members.

Sweden’s defence minister said last month that an application could trigger a number of responses from Russia, including cyber attacks and hybrid measures – such as propaganda campaigns – to undermine Sweden’s security.

Moscow has warned it could deploy nuclear weapons and hypersonic missiles in the European exclave of Kaliningrad if Sweden and Finland become Nato members.

Ms Linde, who will now travel to Canada to discuss security matters with its government, said the US was strongly supportive of Swedish and Finnish membership in Nato, which would increase stability in the Baltic and Arctic regions.

Both Sweden and Finland are expected to make a decision about whether to apply to join Nato this month.