Britain said it monitored a Russian spy ship in the English Channel in recent days and would strengthen its response to secret operations by Russian ships and aircraft in an effort to protect undersea cables.

The Royal Navy has been monitoring a Russian spy ship after it entered British waters, 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.

British Defence Secretary John Healey told parliament Wednesday the Royal Navy was tracking a "Russian spy ship" that passed through UK waters, warning Russia's President Vladimir Putin: "We know what you're doing".

The UK Defence Secretary has warned President Putin “We know what you are doing” after a Russian spy ship was tracked this week in the English Channel by a Royal Navy warship. It comes just weeks after the same ship was caught loitering over critical undersea infrastructure in UK waters.

Defence Secretary John Healey has told Vladimir Putin ‘we see you, we know what you’re doing’ after revealing a Russian spy ship has been off the British coast for two days. In a statement to Parliament this afternoon,