Washington( CNN) Russian military aircraft were spotted flying off the coast of Alaska for the fourth time in as many days, a spokesperson for the North American Aerospace Defense Command told CNN on Friday.

The two most recent sightings resulted late Wednesday and on Thursday, with the first involving two IL-3 8 maritime patrol aircraft and the second involving two Tu-9 5 nuclear-capable Bear bombers.

Russian aircraft never entered US airspace but US F-2 2s and Canadian CF-1 8s planes were dispatched to perform an intercept during Thursday’s encounter, according to NORAD.

The U.S. Air Force’s high-speed stealth fighter

The Cold War: Then and now

Meet the leading player in Syria’s civil war

Will Trump affect the war in Ukraine?

Watch: US F-3 5 plane fighters arrive in Europe

See Russian planes buzz U.S. Navy ship

Kerry: U.S. could have shot down Russian jets