Last week, Moscow threatened undefined “consequences” when it emerged British-made drones had been used by Ukraine to strike targets on Russian soil.
Western intelligence sources have told The Telegraph that Russia has launched a fresh wave of attacks on European armaments factories under the guise of plausible deniability.
A spate of fires and explosions have been reported at plants in Estonia, Italy and Bulgaria, where drones and ammunition were being manufactured for Ukraine.
The Kremlin is recruiting local gang members to sabotage defence manufacturers to test Nato’s resolve.
The attacks appear carefully calculated to fall just short of triggering Article 5, Nato’s mutual defence clause, intelligence officials believe.
A Nato official told The Telegraph: “In recent years, Russia has accelerated its destabilisation campaigns against allies through cyber attacks, assassination attempts and acts of sabotage.”
What has become known as the Kremlin’s “hybrid war”, different officials argue, is aimed at escalating tensions among Nato’s allies and deterring support for Ukraine.
The Nato official added: “Nato continues to boost its resilience and is applying and enhancing the tools at our disposal to counter hybrid actions. We continue to monitor malign activities conducted against allies, including through proxies.
“At every stage, we will ensure that the alliance is prepared to deter and defend against any threat and to keep our one billion citizens safe.”