More than 50 firefighters have been called to deal with a major blaze at the Royal Victoria Hospital site in Belfast.
Ten appliances were deployed to tackle the fire in a new high-rise building which is still under construction.
It broke out on the sixth floor and quickly spread to the seventh and eighth.
While construction workers were evacuated from the building, no hospital services in nearby units were impacted.
Fire Service group commander Stanley Bentley said the incident was being treated as a "major fire".
"But the key thing is the Royal has not been affected," he added. "No patients or staff needed to be evacuated."