Vladimir Putin is testing Nato borders for weak spots, security chiefs warn

Kai Sauer, the Finnish ambassador to Germany, said the recent accession of Finland to Nato was clearly a factor in the manoeuvres by Russia.

“In military terms, our threat perception has not changed, but it seems quite clear that we are facing certain hybrid activities,” he said.

“It is clear that with the Finnish and Swedish Nato membership the geopolitical situation in the Baltic sea has changed. I think it’s also quite predictable that Russia is adapting to that change but how that will manifest itself is less clear.”

Another potential flashpoint is the Swedish island of Gotland, located in the middle of the Baltic Sea between Stockholm and Kaliningrad.

“I’m sure that Putin even has both eyes on Gotland. Putin’s goal is to gain control of the Baltic Sea,” Mr Bydén, the Swedish defence chief, told German news outlet RND.

“If Russia takes control and seals off the Baltic Sea, it would have an enormous impact on our lives, in Sweden and all other countries bordering the Baltic Sea. We can’t allow that... the Baltic Sea must not become Putin’s playground where he terrifies Nato members,” he added.

On Friday, Volodymyr Zelensky, the Ukrainian president, referred to the Estonian incident and warned that Russia was evidently “preparing for provocations in the Baltic region against borders”.

Baltic is Nato’s ‘most fragile’ border

Aliona Hlivco, a former Ukrainian MP and the managing director of the Henry Jackson Society, a security think tank, said she saw disturbing parallels between the latest Baltic dispute and the prelude to Russia’s invasion of Ukraine.

“It is all a means of probing to see how far they [Russia] can go, though they do not currently have the military capacity to go for an actual war with the Baltics,” she said.

The Baltic region, she explained, was “the most fragile border of Nato” not just because it was porous but due to its contingency of “Russian diaspora which they can mobilise through Russian propaganda and TV … we had all these factors in Ukraine”.

Russia is currently rearming its forces as it continues its latest offensive in north-east Ukraine.

But Western leaders such as Boris Pistorius, the German defence minister, have warned that Moscow’s rearmament could also make it ready to attack a Nato state within the next five to seven years.