The United Kingdom has confirmed that one of its Royal Navy nuclear-powered submarines surfaced close to the Yantar, a notorious Russian spy ship late last year, to make it clear it was being observed.

The UK authorized the British submarine to surface closely to the Russian vessel to warn it off, British defense secretary Healey said.

Defence Secretary John Healey said Russia "remains the most pressing and immediate threat to Britain", and added that "any threat will be met with strength and resolve".