A cargo ship, linked to the Russian ghost fleet, which has been investigated for suspicious activity in the Baltic was spotted by an Irish Air Corps aircraft dropping an anchor close to an undersea cable in Irish waters.

It has emerged that the incident earlier this year occured in waters off the north east coast. The Air Corps had dispatched an aircraft to monitor its movements as it is a list of Russian related vessels.

There has been several incidents in the Baltic Sea where anchors, dropped by Russian linked vessels, have damaged critical internet cables.

The Air Corps was able to film the ship, dropping the anchor in the area, and following communication from the Irish crew the cargo vessel fled. It was not confirmed if the ship was intentionally targeting undersea infrastructure or if it was a case of bad seamanship.

The ship, sailing under a flag from Caribbean region, had been in trouble in the Baltic Sea in the same month. German authorities escorted it out of the area along with Swedish and Danish naval colleagues.

On that occasion she was sailing from St Petersburg en route through the waters near Gotland, an island off Sweden.

The sighting of it in Irish waters was made earlier this year and it was being monitored after intelligence was shared from a friendly nation with the Irish State.

An Irish Air Corps maritime patrol vessel was despatched to keep watch – it is understood that they recorded it, using specialist camera equipment, as it dropped the anchor.

It is understood the ship was contacted by radio by the Irish Defence Forces and directed to haul its anchor back up and it departed the area.

The Journal has learned that the ship is back in Irish waters and is heading towards the west coast.

It is understood that the ship has steamed from the Bay of Biscay and is currently off the Cork and Kerry coast.

Using an open source flight monitoring service The Journal was able to follow an Air Corps CASA 295 aircraft which went to a location near the ship this afternoon.

This publication has previously revealed that Ireland held a major exercise behind closed doors to test how Ireland will deal with a complete loss of the internet after a targeted attack.

It is understood that the event, known as a tabletop exercise, was held in February and involved multiple Government departments and agencies including the Defence Forces, An Garda Síochána and other emergency services.

The scenario was a concerted cyber attack which was combined with the loss of multiple undersea cables.

There are a large amount of fibre optic internet cables connecting Europe to the US and other parts of the world running through Irish waters. They carry all high speed internet traffic, including banking and other critical data.