"Even if the fighting ends, we will not return to some kind of normal, friendly, relationship with Russia. Trust has been destroyed," he said. "I think the war has had long-lasting consequences for the relationship with Russia."

He had previewed this stark assessment by claiming that NATO sought to build positive relations with Russia immediately after the Cold War - despite that fact that the military alliance's expansion to Russia's doorstep began soon after the collapse of the Soviet Union, according to admissions from US diplomats.

But he also said there remained the possibility that Moscow could salvage some degree of the prior "trust" that had been shattered by the invasion: 

"They [Russia] can do as many other European countries have done since the end of the Second World War, they can choose peace, choose cooperation, choose to trust their neighbors instead of always being so aggressive and threatening neighbors as Russia has done again and again against Georgia, against Ukraine," Stoltenberg said.

Interestingly, on the same day as the NATO chief's remarks, German Chancellor Olaf Scholz weighed in on relations with Russia and suggested they were not totally destroyed or altogether severed.