April 21 (UPI) -- For the fourth time in as many days, the U.S. military said it detected Russian military planes flying off the coast of Alaska, though they remained far away from penetrating U.S. air space.
The flights posed no danger to the United States, officials said, and did not prompt a U.S. military response. Earlier in the week, U.S. fighter jets were scrambled when Russian planes came 40 nautical miles from the coast of an Alaskan island.
The incident Wednesday involved two IL-38 maritime patrol aircraft. The Thursday incident involved two Tu-95 nuclear-capable Bear bombers. In both instances, the Russian aircraft entered the U.S. Air Defense Identification Zone, a virtual buffer surrounding U.S. air space that allows the military to identify planes potentially entering U.S.-controlled areas. The Russian planes remained in international air space the entire time.
U.S. officials told CNN this kind of "cat and mouse" interaction by the Russian air force is not unprecedented, but hasn't occurred since 2015. The Russians have undertaken similarly provocative military fly-bys in the Black Sea, when a Russian plane buzzed a U.S. Navy destroyer. The Japanese have had to scramble fighter jets four times recently due to Russian planes in close proximity to Japanese air space.