TORONTO — Fighter jets were scrambled to intercept two Russian bombers in the Arctic as they approached Canadian airspace on the eve of a visit from Canada's prime minister to observe an Arctic military exercise, a spokesman for the prime minister said Wednesday.

Dimitri Soudas, Stephen Harper's director of communications, said two Canadian CF-18 jets shadowed a pair of Russian Tu-95 Bear jets in international airspace Tuesday.

Soudas said the bombers flew within 50 kilometers of Canadian soil. They were first spotted about 120 nautical miles north of Inuvik, Northwest Territories.

"Thanks to the rapid response of the Canadian Forces, at no time did the Russian aircraft enter sovereign Canadian airspace," Soudas said in an e-mail.

Soudas warned that the North American Aerospace Defense Command, a joint U.S. and Canadian agency, "carefully monitors all air activities in the north and considers all options to protect the air sovereignty of Canada and the United States."

Harper was to observe an annual military exercise in the Canadian Arctic on Wednesday. Soudas said Harper was briefed during and at the conclusion of the intercept mission. He said the Canadian jets returned to base without incident.

Canada has linked recent Russian flights in the area to the competition between Canada, Russia, the United States and other countries to secure Arctic resources. With polar ice melting there are new opportunities to exploit the region's oil, gas and mineral reserves.

Two Russian bombers were intercepted last month off Canada's East Coast near the Arctic.