Six elderly residents of a private nursing home have died after a suspected outbreak of a virus.
All of those who died at Nazareth House at Fahan, near Buncrana, Co Donegal, over the past two weeks were over the age of 80 years, it is understood.
Five died in "a cluster" over the past five days, said the Health Service Executive (HSE).
It is believed there are 39 remaining residents in the care home, overlooking Lough Swilly, which had been run by the Sisters of Nazareth, a religious order of nuns.
Of these, 27 have also shown signs of respiratory illness.
Swabs have been taken from these affected elderly residents which have been sent for analysis in Dublin.
It is expected they will confirm the nature of the outbreak by Tuesday evening.
Dr Darina O'Flanagan, director of the Health Protection Surveillance Centre, said it is suspected the deaths were as a result of a respiratory-related virus outbreak.
This could be a particular strain of influenza prevalent this year, which was more likely to affect older people.
"If this is flu, there is a type of virus this year that is more associated with the elderly," she said.