NORAD intercepts three groups of Russian planes near Alaska

The Russian Tu-142 planes entered the Alaskan Air Defense Identification Zone, which extends outward from North America, late Thursday and came "within 50 nautical miles of Alaskan shores," a NORAD statement said.

It added, though, that the Russian planes never entered United States or Canadian sovereign airspace, and instead "loitered within the ADIZ" for about five hours before departing.

The practice of chasing Russian planes from U.S. airspace has become common in 2020.

"Our northern approaches have had an increase in foreign military activity as our competitors continue to expland their military presence and probe our defenses," Gen. Glen D. VanHerck, commander of NORAD, said in the statement.

"This year, we've conducted more than a dozen intercepts, the most in recent years. The importance of our continued efforts to project air defense operations in and through the north has never been more apparent," VanHerck said.

In June, NORAD aircraft intercepted four Russian planes entering the ADIZ.

F-22 planes, with assistance from KC-135 air refuelers and E-3 Airborne Warning and Control System, intercepted the Russian planes as they came within 65 nautical miles of the Aleutian island chain off the coast of Alaska.