(Adds dismissive Russian reaction paras 3-5)
By David Ljunggren
OTTAWA, Feb 27 Canadian fighters scrambled to intercept an approaching Russian bomber less than 24 hours before U.S. President Barack Obama's visit to Ottawa last week, Canadian Defence Minister Peter MacKay said on Friday.
The long-range Bear bomber did not enter Canada's Arctic airspace but the two Canadian CF-18 fighters had to order the plane to "back off", MacKay told a news conference.
He also told reporters that Russia had not warned Canada that the flight was coming, a statement that a Russian government source in Moscow dismissed as farcical.
The Russian government source said Canada had been informed about the flight before it took off.
"So the statements from Canada's defense ministry are perplexing to say the least and cannot be called anything other than a farce," Interfax news agency quoted the source as saying.
Obama spent a few hours in the Canadian capital on Feb. 19 on his first foreign trip since becoming president.
"I'm not going to stand here and accuse the Russians of having deliberately done this during the presidential visit but it was a strong coincidence, which we met with the presence, as we always do, of F-18 fighter planes ... and sent a strong signal that they should back off and stay out of our air space," MacKay said.
MacKay also said Russia had stepped up its bomber flights toward the Canadian Arctic in the last few years, reviving a practice that was common during the Cold War.
Canadian Prime Minister Stephen Harper said he was very concerned by the incident.
"I have expressed at various times the deep concern our government has with the increasingly aggressive Russian actions around the globe and into our airspace," he told a news conference in the western province of Saskatchewan.
"We will defend our airspace ... we will respond every time the Russians make any kind of intrusion on the sovereignty of Canada," he said.
MacKay did not say exactly when the incident occurred or how close the bomber came to Canadian airspace.
"It's not a game at all. These aircraft approaching Canadian or U.S. airspace are viewed very seriously," he said.
"We have asked on a number of occasions ... that we are given a heads up when this type of air traffic is to occur and to date we have not received that kind of notice."
MacKay spoke after a meeting with U.S. General Gene Renuart, commander of the binational North American Aerospace Defense Command (NORAD).
"They (the Russians) have been professional in the way they have conducted their aircraft operations," Renuart said.
Canada's minority Conservative government has promised to spend billions of dollars boosting Canada's presence in the Arctic, which scientists believe has vast reserves of oil and natural gas.
"Our intention is very much to demonstrate our sovereignty, our capability to protect our territory, our airspace, our water (and) our people in the Arctic and that includes our resources," MacKay said.
Five countries with an Arctic coastline -- Russia, the United States, Canada, Norway, and Denmark through its control of Greenland -- have competing claims to the region.
Russia said this week it would respond to any moves to militarize the Arctic.
Ottawa -- which plans to build a deep water port in the region -- has stepped up sovereignty patrols in the Arctic and last August it said it would toughen reporting requirements for ships entering its waters in the Far North. (With additional reporting by Rod Nickel in Saskatoon and Reuters Moscow bureau; Editing by Peter Galloway)