In Thusis, in Switzerland's far-east, a "major fire" that broke out just after midnight "entirely burned" a building that housed a restaurant and residential flats, regional police in Graubunden canton said in a statement.
"The stairwell collapsed, so the roof of the building had to be opened with a crane," it said, adding that five people remained missing.
Police said 14 people had managed to escape the burning building.
Eight of them were hurt, including two who were in serious condition, they said.
The injured had been transported to hospitals across Graubunden and in Zurich.
Around 100 firefighters were sent to the scene, where crews were still working to extinguish the fire Friday morning.
An investigation has been launched to determine the cause of the blaze, which police said had started on the second floor of the building.
A photo released by the police showed a multi-story apartment building engulfed in smoke with flames shooting out of several windows on the upper floor and into the night sky, setting the roof ablaze.
In a separate incident late Thursday, a fire broke out in the kitchen of an apartment in a building in the northern city of Schaffhausen, near the German border.
"Eleven people were injured, nine of whom have been taken to hospital," local police said in a statement, adding that a police officer was among the injured.
Police said firefighters had managed to prevent the blaze from spreading to other units in the building.
