A fire broke out at Irish Naval Base on Haulbowline Island, Cork, on December 21 and was extinghuished within a few hours.
The blaze started on the upper floor of a disused building at the Naval Base at 8:30 p.m. local time, Irish Defence Forces said in a statement.
There were no casualties reported.
Two units of Carrigaline es Fire Service, alongside Naval Service fire crews, tended the fire and were assisted by a further three units from Midleton, Crosshaven and Cork.
A Garda Síochana also attended the scene and the surrounding area was evacuated as a precaution.
A full investigation will be carried out in order to establish the cause of the fire, according to the statement.