Russia has capacity for a limited attack against NATO territory at any time but a decision to act would depend on the Western allies' posture, a top German military official warned, Reuters reported.

"If you look at Russia's current capabilities and combat power, Russia could kick off a small-scale attack against NATO territory as early as tomorrow," Lieutenant General Alexander Sollfrank told Reuters in an interview.

"Small, quick, regionally limited, nothing big - Russia is too tied down in Ukraine for that."

Sollfrank, who heads Germany's joint operations command and oversees defence planning, also echoed NATO warnings that Russia could potentially mount a large-scale assault on the 32-member alliance as early as 2029 if its armament efforts persist, according to Reuters.