The alliance stressed that although the exercises had been planned before the invasion of Ukraine, it would "remain vigilant" toward nuclear threats from Moscow.
NATO on Monday began its annual series of nuclear preparedness drills on the heels of veiled threats from Russian President Vladimir Putin that he might consider a nuclear option after military setbacks in Ukraine.
The alliance stressed, however, that the drills are a "routine, recurring training activity" that had been planned before Russia invaded Ukraine. A NATO press release stated that the drills are "not linked to any current world events."
"It would send a very wrong signal if we suddenly now cancelled a routine, long-time planned exercise because of the war in Ukraine," NATO Secretary-General Jens Stoltenberg said last week.
"We need to understand that NATO's firm, predictable behavior, our military strength, is the best way to prevent escalation."
Stoltenberg added that the 30-nation group would however "remain vigilant" about the threat from Moscow.
The drills, which run until October 30, are taking place mostly in Belgium, the UK, and the North Sea.
They involve US B-52 bombers as part of 60 total aircraft participating in training flights. Also among the aircraft involved in the drills are fourth and fifth generation fighter jets, as well as surveillance and tanker aircraft, the alliance said in a press release.
Meanwhile, Russia is set to hold its own annual nuclear drills, named "Grom" (Thunder), which are routinely conducted in late October.
Nuclear threats from Moscow
Russian President Vladimir Putin, and other Russian officials; have at multiple occasions alluded to Russia's nuclear arsenal since the start of the invasion of Ukraine.
Last month, Putin said "our country also has various means of destruction," adding that Moscow will use "all means at [its] disposal to protect Russia."
On Wednesday, the British daily The Times reported, citing NATO sources, reported that Russia was preparing nuclear tests in the Black Sea.
NATO Secretary-General Jens Stoltenberg said on Thursday that Moscow will face "severe consequences" if it launches a nuclear strike on Ukraine. He added that the circumstances for NATO to use a nuclear weapon were "extremely remote." The alliance includes three nuclear powers: the US, the UK and France.