The "routine" intercept of the Russian planes -- which included Tu-95 bomber and Su-35 fighter aircraft -- occurred Monday, NORAD said in a statement.

"Russian aircraft remained in international airspace and did not enter American or Canadian sovereign airspace," it said, adding that such Russian activity "occurs regularly and is not seen as a threat, nor is the activity seen as provocative."

While the intercept of the Russian aircraft was routine, US warplanes stationed in North America saw rare offensive action this month, shooting down an alleged Chinese surveillance balloon and three unidentified objects.