Danish intelligence warns Russia could attack a NATO country within months

In a report released Thursday, the DDIS said a limited military attack would be a desperate move by Russia and, like intensified hybrid attacks, could take place in the coming months. It said the purpose would be to redirect European resources away from supporting Ukraine and to sow division within NATO if the alliance fails to agree on a collective response.

The agency said it saw no indications that Russia would launch an outright invasion of a NATO country, though it could not rule such a move out. Russia could also deploy a limited number of troops, possibly without national insignia, into NATO countries on its border, the DDIS said. It added that such a build-up would be difficult to conceal and would take several months to prepare.

The threat assessment follows a series of warnings from senior European security officials and lawmakers in recent days. NATO members bordering Russia include Finland, Norway and Poland, as well as the Baltic states of Latvia, Estonia and Lithuania.

On Thursday, Poland's government said a blaze at a Starlink ground station in the country was an act of sabotage aimed at disrupting internet services, including for Ukraine's military. Polish Deputy Prime Minister Krzysztof Gawkowski said it had not yet been established who was responsible for the fire, but that many signs suggested it aligned with Russia's new doctrine of attack, according to Reuters.

A spokesperson for Russia's Embassy in London was not immediately available to comment when contacted by CNBC. The Kremlin has previously denied involvement in similar incidents.

Denmark's intelligence also warned that Russia will intensify its hybrid war by carrying out more attacks against the West and NATO, with greater consequences for targeted countries than in the past. These could include major cyberattacks that seriously damage vital societal functions, as well as sabotage attacks with a high risk of casualties, the DDIS said.