The British navy said Wednesday that is ramping up measures to protect its waters from secret Russian operations after identifying a Russian spy vessel in UK waters for the second time in weeks.

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.

A Russian spy ship entered British waters twice in recent weeks, prompting the UK to deploy Royal Navy ships, Royal Air Force planes and a submarine, Defence Secretary John Healey said.