US fighter jets intercepted Russian bombers and warplanes in international airspace off the coast of Alaska Tuesday, in the fourth and fifth such incursions this year, US military officials said on Wednesday.

The U.S.-Canadian airspace defense agency said two Russian bombers accompanied by two Su-35 fighter jets entered the Alaskan Air Defense Identification Zone (ADIZ) and were intercepted by two NORAD F-22s.

“Russian aircraft remained in international airspace and never entered US or Canadian sovereign airspace, but this time, the Russian planes flew in and out of the Alaska Air Defense Identification Zone that stretches 200 miles from the Alaska coastline,” the North American Aerospace Defense Command tweeted.