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The inspection comes just days after Canada flew over Russia aboard a Hungarian aircraft, and it highlights the frequent surveillance that goes on between the two countries.

Little known even to some experts in the defence community, Canada has invoked the treaty to fly over Russia four times annually since 2004 — that is roughly 30 inspections in eight years.

There is a treaty, but we have to be very, very, very cautious not to forget past espionage cases

Houchang Hassan-Yari, a Royal Military College of Canada political science professor, said while the two countries are operating under the treaty, Ottawa should be vigilant when Russia’s Tupolev aircraft flies over Canada some time between Tuesday and Thursday.

“There is a treaty, but we have to be very, very, very cautious not to forget past espionage cases,” Mr. Hassan-Yari said. “We should not forget that the relationship between Russia and Canada was not necessarily friendly even 20 years ago, so who knows what will happen in the next 20 years.”

Canadian military personnel will “escort” the Russians for the sake of security and compliance, National Defence officials said.

The treaty gives Canada the explicit right to send at least two flight monitors and one interpreter aboard the unarmed Russian aircraft, which will use onboard imagery systems to “observe and verify objects of interest or concern,” the statement says.

“[Flyovers] are part of the game,” said Peter St. John, a University of Manitoba professor who specializes in security issues. “There is a lot of [tit-for-tat] that goes on … It just might not typically be public knowledge.”