Bobylyov said that investigators at Hospital 17 said the first call to the fire department had come very late.
"The hospital personnel worked very badly, they did not take steps to evacuate people in the early stages of the fire," he said.
The drug rehabilitation unit also had its windows barred and only one exit, which further complicated the operation, said Andrianova.
There were differences in the number of casualties reported.
Emergency ministry officials said that about "100 people were rescued and 50 were hospitalised".
Firefighters used 20 fire engines to extinguish the fire in a two-hour operation.