The head of the HSE is describing the ransomware attack as 'unfair, unjust and incomprehensible'.
Paul Reid says he's 'gutted and angry' after what the country's been through with Covid-19.
The executive says the ransomware attack has had an 'disabling effect' on the health service, and will take several weeks to resolve.
It's led to widespread cancellations - but Liam Woods, the HSE's director of acute operations, says it won't affect staff getting paid:
Meanwhile, the service disruptions at Letterkenny University Hospital as a result of the ransomware attack are expected to continue for the rest of this week.
All outpatient, diagnostic and endoscopy clinics are cancelled.
All elective inpatient and day case procedures are cancelled also however, a small number of procedures may go ahead - patients will be contacted directly.
People attending the Emergency Department can expect significant delays as existing IT systems are not in use and manual workarounds in place are time-consuming.
Saolta is advising patients that where possible they should bring their existing patient or hospital number with them or any letter they have received from the hospital as this will contain information which will make it easier to find existing medical records.
Maternity services and dialysis treatment are continuing at the hospital as normal and patients are advised to attend their chemotherapy appointments unless contacted and advised otherwise.