A search has confirmed there was nobody inside a disused school which caught fire last night, the fire service said.
Crews were called to Ronald Avenue in Llandudno Junction, Conwy, just after 19:00 GMT on Monday.
The building was searched after concerns were raised there may be people inside, North Wales fire service said.
The fire was out by midnight and nobody was found inside the former Ysgol Nant y Coed, which closed in 2016.
The building remains the property of Conwy County Borough Council.
Llandudno Junction councillor Mike Priestley described the incident as "quite serious" and said it was a "shock that a fire has broken out on a secure site".
The cause of the fire is not known.
Mr Priestly said: "We need to wait and see what the result of the investigation is."
But he added: "I'll be talking to the council and the local police about the security on this site for the future."
Mr Priestly is campaigning for the site to be redeveloped as a medical facility for the area.