Russia is holding extensive war games in the Arctic this week, including cruise missile tests and a flight over the North Pole by strategic bombers.
The military exercises come on the heels of a controversial scientific expedition which last week planted a titanium Russian flag on the seabed 4-kilometres beneath the Pole to signify Moscow's claim to own a big slice of the Arctic.
The RIA-Novosti agency quoted airforce sources as saying that four supersonic Tu-160 strategic bombers and 14 medium-range Tu-22M bombers are involved in the exercises, which will include a flyover of the 1.2-million square kilometre Arctic territories claimed by Russia.
Moscow argues that the Lomonosov Ridge, which underlies the Arctic, is an extension of the Siberian continental shelf and therefore subject to Russian sovereignty.
Two scientific expeditions, including last week's flag-planting exercise at the North Pole, have been sent so far this year to gather data to back up Russia's claim before the United Nations commission that rules on territorial zones.
A third mission, including a nuclear-powered icebreaker and at least one deep-sea submersible, is slated to leave for the Arctic in the coming weeks.
Other Arctic countries have condemned Russia's actions as political theatre that has no legal implications, but the event has nevertheless triggered a flurry of activity from some.
Canada this week announced that it, too, will hold military exercises this week in the Arctic territory near Baffin Island, and Canadian Prime Minister Stephen Harper embarked on a three-day tour of the North.
In the wake of Russia's flag-planting, the U.S. ordered a Coast Guard icebreaker, the USS Healy, to conduct research in the high Arctic near Alaska.