Two Russian military aircraft were detected Wednesday operating in the international airspace off of Alaska, NORAD said.

The aircraft were operating in airspace known as the Air Defense Identification Zone, or ADIZ, that stretches 150 miles from the coastline, an area where aircraft are asked to identify themselves.

"The Russian aircraft remained in international airspace and did not enter American or Canadian sovereign airspace," NORAD said. "This Russian activity in the Alaska ADIZ occurs regularly and is not seen as a threat."

The U.S. does not appear to have launched intercepting aircraft, with NORAD saying in a press release that the Russian aircraft were “detected and tracked."

United States and Canadian fighter jets in July intercepted four Russian and Chinese bombers flying in international airspace near Alaska, officials said at the time.

NORAD did not identify what type of Russian aircraft were involved in Thursday's incident.

This is a developing story. Please check back for updates.