The British navy said Thursday it tracked a Russian submarine navigating through the English Channel for three days, as it steps up efforts to police its seas against such threats.

A British naval supply ship with an on-board helicopter was deployed to track the stealthy Kilo-class submarine Krasnodar and the tug Altay, the Royal Navy said in a statement .

The Russian ships had arrived from the North Sea and entered the Channel.

"Expert aircrew were prepared to pivot to anti-submarine operations if Krasnodar had dived below the surface," the statement said.

But it sailed on the surface throughout the operation, despite unfavorable weather conditions.

"There is nothing like a Russian submarine to focus the mind for any mariner," Royal Navy Captain James Allen said in a statement .

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