Firefighters put out a blaze at an empty listed building in Newry, County Down, on Saturday night.
The cause of the fire at Sandy Street in the city is not yet known.
Alan Fulford, of the Fire Brigade, said the flames were spreading when officers arrived at the scene.
"When the appliances arrived there was two floors quite well alight substantial fire on the first floor which had spread to the second floor," he said.
"This was a mid-terrace block of flats, four storeys high. The fire here was in a block of unoccupied flats the premises next doors are also unoccupied.
"But we think the premises on the other side, although they were secure, appear to be occupied.
"This appears to be a block of listed buildings, perhaps four or five within the one block."