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 Royal Navy has been monitoring a Russian spy ship after it was spotted around UK waters earlier this week, the defence secretary has told MPs. John Healey said the vessel, Yantar, was used for gathering intelligence and mapping the UK's critical underwater infrastructure.

A Royal Navy submarine was authorized to surface close to a Russian ship "strictly as a deterrent measure," British Defense Secretary John Healey said.