The North American Aerospace Defense Command said Tuesday that Russian warplanes were flying off the coast of Alaska and were being tracked by the U.S. military.

NORAD made it clear that the planes were not a threat and that they did not go into Canadian or American airspace, according to CBS News.

The number of planes was also not made clear. 

"NORAD employs a layered defense network of satellites, ground-based and airborne radars and fighter aircraft to detect and track aircraft and inform appropriate actions," the aerospace and defense company said in a statement. "NORAD remains ready to employ a number of response options in defense of North America."

Russian military activity was also detected near Alaska in February and in December of last year.