Finland and Sweden joined forces to intercept a Russian warplane flying over the Gulf of Finland – the first such joint operation by the Nordic countries.

Swedish Prime Minister Ulf Kristersson said the operation, which took place on Thursday, showed how the so-called Quick Reaction Alert co-operation could monitor and safeguard both countries’ airspace.

‘It is a concrete expression of the readiness and trust we have built together – and an expression of the strength in the Nordic, Nordic-Baltic, and broader Nato cooperation in our part of the world,’ Kristersson wrote in a post on X today.

‘The Baltic Sea has never been as vulnerable as it is now – but it has also never been better protected than it is right now,’ he said.

The two air forces’ jets tracked down and identified a group of Russian aircraft including a transport plane and several fighter jets, the Finnish Air Force said.

The Baltic Sea region, of which the Gulf of Finland is part, is on high alert after incidents involving gas pipeline outages, airspace violations and drone sightings since Russia’s 2022 full-scale invasion of Ukraine.

Meanwhile, fears are growing in the wider continent that Vladimir Putin is plotting an attack on European countries. 

Finland and Sweden both joined Nato following the invasion of Ukraine, departing from a longstanding policy of non-alignment.

Finland and Sweden said today they had scrambled fighter jets to intercept and identify Russian military aircraft

The two air forces’ jets tracked down and identified a group of Russian aircraft including a transport plane and several fighter jets, the Finnish Air Force said

Finland and Sweden both joined Nato following Russia’s 2022 invasion of Ukraine

Their Nordic neighbors Norway, Iceland and Denmark were already members of the Atlantic alliance, as were the three Baltic republics of Estonia, Latvia and Lithuania.

It comes as the Danish Defence Intelligence Service (DDIS) said on Thursday that the risk of Russian military action against Nato countries was growing and an outright invasion was ‘highly unlikely’ but possible.

European countries have been on high alert for any Russian interference, with fears that Moscow could target Kyiv’s Western backers as the Kremlin’s invasion of Ukraine drags on into its fifth year.

‘There is a low but growing risk that Russia will launch a limited military attack against one or several Nato countries bordering Russia,’ Thomas Ahrenkiel, the head of the DDIS, told a press conference at which he presented an updated assessment of the threat from Russia.

He said that the agency still considered it ‘highly unlikely that Russia would see any interest in invading a Nato country, but we cannot rule it out’.

In the assessment, the agency said that Russia would likely carry out more so-called ‘hybrid attacks’ against targets in the West.

It noted that in the past such attacks had ‘mainly been aimed at creating fear and weakening public support for aid to Ukraine’.

But they had now started to include actions meant to stop support from reaching Ukraine, such as sabotage against defence companies or railway transports carrying military equipment, the agency said.

The DDIS said it thought Russia would intensify such attacks, which could also include ‘destructive cyber attacks that cripple critical societal functions’.

The agency also said there was a low risk of a limited military attack even if the war in Ukraine continued, as an attempt to redirect European resources away from Ukraine.

‘A limited military attack would be a desperate move on Russia’s part and, like the intensified hybrid attacks, could potentially take place in the coming months,’ the agency said.

Swedish Prime Minister Ulf Kristersson said the operation showed how the so-called Quick Reaction Alert cooperation could monitor and safeguard both countries’ airspace

Danish Soldiers take part in a Nato military exercise

However, the DDIS also noted that ‘a build-up of forces would require several months of preparation and will be difficult to conceal’.

Mr Ahrenkiel also stressed that although ‘Russia’s increased willingness to take risks has consequences for the security situation in Denmark’, notably through hybrid attacks, this does not mean that Russia is going to attack the Scandinavian country.

‘We do not expect a conventional Russian military attack against Denmark,’ he said.

Denmark’s national intelligence and security service PET meanwhile said in a statement that Russia’s increased willingness to take risks ‘may lead to an increase in both Russian influence activity and the espionage and sabotage threat in Denmark’.

PET had previously indicated that sabotage threats primarily target the defence industry and others directly linked to the military support of Ukraine.