Canadian and American fighter jets were scrambled to intercept Russian war planes over the Arctic in two separate incidents this week.
Norad, the North American Aerospace Defence Command, says the Russian planes did not violate Canadian or U.S. airspace in either case.
Norad spokesman Lt. Col. Michael Jazdyk says the first incident occurred Wednesday night west of Alaska when American fighter jets intercepted six Russian aircraft, including fighter jets and bombers.
He says in the early hours of Thursday morning two Canadian CF-18 fighter jets intercepted two Russian bombers over the Beaufort sea.
It's not uncommon for Russian planes to fly in the area and Norad routinely sends fighters up to investigate.
Jazdyk says Canadian or American fighters have intercepted some 50 Russian planes over the last five years.
The aircraft intercepted this week stayed in international air space but were flying in an area called the Air Defence Identification Zone, jointly administered by Canadian and American civil and military air authorities.
The zone rings most of North America and aircraft that enter it are required to radio their planned course and destination _ those that don't can be intercepted by military aircraft.
"We monitor everything coming into our air space, so we obviously go out there, go investigate, make sure it's not a threat, said Jazdyk in an interview.
"They're in international airspace so there is no reason they can't continue, but we'll monitor that, make sure there is no threat."
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