Russian attack submarines have conducted missions around the Irish Sea twice since the 2022 invasion of Ukraine, Bloomberg News reported on Monday, citing three people familiar with the matter.

The first deployment of a Russian Kilo-class submarine close to the Irish Sea, happened around 18 months ago while the second occurrence took place more recently, the report added.

The extent of the submarine movements went beyond what British officials had previously seen, it said.

U.S. officials were aware of the sub movements, the report further said citing two people familiar with the matter.

Russia’s and Ireland’s defense ministries, Britain’s foreign ministry and the White House did not immediately respond to Reuters’ requests for comment.

The Kilo-class submarine is a diesel-electric attack submarine capable of firing Russia’s Kalibr cruise missiles, as well as torpedoes and naval mines, Bloomberg said.

Russia in 2022 said its navy would stage a sweeping set of exercises involving all its fleets from the Pacific to the Atlantic, the latest show of strength in its military standoff with the West.

Irish Foreign Minister Simon Coveney commented at the time that they were not welcome.