Two Russian IL-38 military aircraft were detected and tracked while operating in the Alaska Air Defense Identification Zone (ADIZ) on Sept. 14, marking the third such incident in one week, the North American Aerospace Defense Command (NORAD) reported on Sept. 15.
The Russian planes remained in international airspace and did not violate U.S. or Canadian airspace, NORAD reported. The flights are "not seen as a threat."
Earlier in the week, NORAD on Sept. 11 said it detected two Russian military aircraft operating in the ADIZ. Two days later, the agency on Sept. 13 detected a pair of Russian Tu-142 military aircraft in the area.
NORAD defines the ADIZ as a "stretch of international airspace that requires the ready identification of all aircraft in the interest of national security."
Earlier this summer, the U.S. and Canada, which make up NORAD, scrambled fighter jets to intercept Russian and Chinese military planes in the ADIZ on July 25. NORAD in mid-August also detected and tracked four Russian warplanes flying in the ADIZ.
According to NORAD, such incidences occur "regularly."