The Irish Naval Service is keeping the 350ft Russian spy ship under observation. The ship named ‘Yantar’ has served in the Russian Navy since 2015.
It is operated by Russia’s secretive Main Directorate of Underwater Research - which controls many of Russia’s special mission submarines.
The vessel carries extensive surveillance equipment and can deploy three-man submersibles which can dive to around 20,000ft.
“Defence Forces Ireland can confirm that the Irish Naval Service is aware of the Russian ship Yantar transiting in the Irish exclusive economic zone off the west of Ireland," a statement read.
“This ship is transmitting on the automatic identification system and is outside Irish territorial waters.
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“This activity is in line with the UN Convention on the Law Of the Sea (UNCLOS) rules for transit through international waters.
“Territorial waters are 12 nautical miles from the coast of Ireland and under UNCLOS, there is no restriction on ships operating on the high seas inside exclusive economic zones.”
The Yantar, which is in the Russian navy, arrived without warning off the Donegal coast on Tuesday.
The ship is reportedly involved in cable cutting and intelligence missions and has the capability to lay underwater traps.
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Back in May, the UK’s latest aircraft carrier was intercepted by Russian spy ships just hours after setting sail.
Two Russian spy ships positioned in waters off Northern Scotland intercepted the vessel.
The Auxiliary General Intelligence Gathering vessels, part of Russia’s Northern fleet, featured listening and interception equipment.
The ships were later identified by a US Navy P8 maritime patrol aircraft, based at RAF Lossiemouth.