Fears are growing for an elderly brother and sister missing after a fire at a farmhouse near Falkirk.
Emergency services were called to the house at Castlerankine Farm, near Denny, at 0345 GMT on Thursday, when the building was already "well ablaze".
Farmer David Miller, 65, and his 75-year-old sister May have not been seen since the fire broke out.
The blaze flared up again overnight and police said it was still not safe to enter to search the building.
A Central Scotland Police spokeswoman said the fire was "believed not to be suspicious".
A local farmer helped fire engines and police reach the farmhouse in the early hours of Thursday, by towing them up its snow-covered access track with a tractor.
A spokesman for Central Scotland Fire and Rescue said four fire engines - from Denny, Larbert, Stirling and Falkirk - were sent to the scene, together with a water-carrier, because of the remoteness of the location.
The fire service's area manager, Kenny Rogers, said: "It's quite remote and the fire was well involved when we arrived and the flames were through the roof.
"It was very severe. The roof then caved in and the building pancaked onto the ground floor.
"We put out the flames - that was relatively straightforward - but we were unable to enter the building because it was too dangerous."
The police spokeswoman said: "Preparatory work will be carried out over the weekend to make the building safe to allow the search to be carried out.
"The anticipation is that we will be in a position to carry out a search early next week."
She said officers would remain at the scene over the weekend.