A third baby has died after an outbreak of a deadly infection in a hospital.
The latest death was confirmed as staff at Belfast's Royal Hospital launched an investigation to trace the killer bug at Northern Ireland's biggest maternity unit, which will undergo a deep clean.
Northern Ireland health minister Edwin Poots said expectant mothers are likely to be transferred to other hospitals in the Irish Republic and Britain.
The deaths are believed to be linked to the pseudomonas infection, which can cause severe breathing and other problems.
Pseudomonas aeruginosa is bacteria found in soil, water, plants and animals, and is particularly harmful to those who are already ill, including the elderly with reduced immune systems.
Admissions have been restricted to all but the most seriously ill babies who cannot be treated elsewhere, but staff believe the infection has not spread to other areas of the Royal Victoria Hospital site.
The first two babies to die were born prematurely.
Dr Richard Wright, associate medical director at the Belfast Health and Social Care Trust said: "We are engaged in a fairly major investigation to identify the cause of the infection."