Moscow hit back at Defence Minister Peter MacKay on Friday, calling the minister's comments about the flight of two Russian bombers a "farce," the Russian news agency Ria Novosti reported Friday.

The rhetorical sparring comes after two long-range Russian bombers flew near Canadian airspace in the arctic less than 24 hours before President Barack Obama visited Ottawa on Feb. 19 - an occurrence which MacKay called a "strong coincidence."

Two Canadian CF-18 fighters intercepted the Russian aircraft and MacKay warned Russia on Friday to "back off" from flying near the Canadian border.

The incident has ignited a fierce debate about territorial sovereignty as European nations, Canada and the U.S. squabble about claims in the arctic.

But Russia sent a clear response to MacKay's warnings.

"The Canadian defense minister's statements concerning the flights of our long-haul aircraft are totally unclear," a Russian military source said Friday, adding that the flight was routine.

"The countries adjacent to the flight path had been notified and the planes did not violate the airspace of other countries. In this light the statements by the Canadian Defense Ministry provoke astonishment and can only be called a farce," the source told Ria Novosti.

At a press conference Friday, Defence Minister Peter MacKay said the incident happened on Feb. 18.

"At no time did Russian airplanes enter Canadian airspace but within 24 hours of the president's visit here to Canada last week we did scramble two CF-18 fighter planes from Norad (North American Aerospace Defense Command) and Canada command," MacKay said.

The jets took off from Cold Lake, Alta., to intercept the aircraft, which has been reported as either a Tupolev Tu-95 bomber or its newer sister, the Tu-160.

"They met a Russian aircraft that was approaching Canadian airspace and, as they have done on previous occasions, they sent very clear signals that are understood that that aircraft was to turn around, turn tail, and head back to its own airspace -- which it did," MacKay said.

CTV's Ottawa Bureau Chief Robert Fife said the plane was intercepted about 190 km northeast of Tuktoyaktuk, N.W.T.

"Obviously what they were doing was testing Canadian security knowing full well that all of our security attention would be focused in Ottawa around the president's visit," Fife said.

MacKay said similar incidents have happened in the past. However, he said the frequency of the incidents is increasing.

"For that reason, it puts the emphasis back on the importance of Norad, the importance of our being diligent in defending our airspace, exercising that sovereignty," he said.

"The most obvious way to do that is by using the equipment at our availability, using the existing systems that are there at Norad for this very purpose."

MacKay was in Ottawa Friday meeting with Gen. Walter Natynczyk, Canada's chief of defence staff, and Gen. Gene Renuart, the commander of Norad and USNORTHCOM, to discuss Canada-U.S. military relations.

Renaurt said it was vital that Canada and the U.S. maintain "the solid, integrated air defence posture that we have."

Political fallout widens

Meanwhile, Prime Minister Stephen Harper said Russian intrusions are a "real concern" to his government.

"We will continue to respond, we will defend our airspace," Harper told reporters in Saskatoon.

A Russian air force spokesman said Friday that the flight was planned in advance and was part of routine patrols.

Canadian navy Lt. Desmond James, a spokesman at Norad headquarters in Colorado Springs, Colo., told The Canadian Press that the Russians include long-range flights as part of their training.

"On our part, we go up to make sure they know that while they are doing their training, we do know that they're there and we are watching, prepared to respond should they decide that they're going to alter their course in a threatening manner," James said.

"We have to let the Russians -- any aircraft -- know that we are in a position to respond."

Norad spokesperson Michael Kucharek said it is not atypical to see Russian aircraft engaging in training exercises so close to Canadian airspace.

"This has happened quite often, this is a pattern that we generally see through Russian exercises of this type," he told CTV Newsnet on Friday afternoon.

He estimated that Norad had seen Russian fighters undertaking similar training exercises at least 20 times "over the course of the last couple of years."

During the Cold War, Russian aircraft frequently entered into North American airspace and were often escorted back to international air space by Canadian and American jets.

Brewing international dispute

After the Soviet Union collapsed, the flights were suspended but have resumed in recent years as Russia tries to push its claim on the Arctic.

In total, five countries claim parts of region -- Russia, Canada, Norway, Denmark, and the United States.

Canada has claimed the Northwest Passage.

"The Russians have been very strict about following international rules but they're going right up to the limits," Rob Huebert, with the University of Calgary's Centre for Military and Strategic Studies, told CTV Newsnet Friday.

"If in fact we see the Americans pushing us on the Northwest Passage and ultimately somehow it becomes accepted that it's an international strait I would suspect you'd be seeing Russian bombers coming through the Northwest Passage."

Last summer, then-foreign affairs minister David Emerson said recent actions of Russia in the Far North were of "great concern" to the government.

He said Canadian officials had "seen much increased activity in terms of Russian overflights of Canadian airspace."

Emerson also said the Americans were seeing the same thing around Alaska.

With files from The Canadian Press