Two babies have died at the Royal Victoria Hospital in Belfast after an outbreak of an infection.
The infection is said to be Pseudomonas, which can be particularly harmful to infants who are already ill.
Admission to the neonatal unit at the hospital is being restricted.
The Royal representative said: "Sadly two ill babies have died whose deaths may be linked to this outbreak. We are supporting these families at this very difficult time.
"We are in the process of investigating the outbreak and taking all steps to identify the source."
To help prevent the spread of this infection, everyone, including parents and guardians, is being asked to be diligent in their hand hygiene when entering and leaving the unit.
The situation will be kept under constant review.
