Canada is sending two icebreakers to the High Arctic to gather scientific data in support of its plan to bid for control of the sea floor under and beyond the North Pole.

The coast guard vessels have set out on a six-week journey that will take them to the eastern side of the Lomonosov Ridge.

The undersea ridge starts near Ellesmere Island and runs northward over the pole.

Some say the ridge could give Canada a claim on a vast section of Arctic sea floor.

Others point out that both Denmark and Russia argue the ridge extends from their shores and the pole is on the side of the ridge that is actually closer to Greenland.

Under a U.N. treaty that controls sea-floor claims, overlapping bids must be settled through negotiation.