The remaining 24 patients were safely evacuated, including some who had to be carried out of the building, and the four medical personnel working at the home were unhurt, they said.
The fire raised additional concern in Russia because it followed two similar fires in 2013 that took the lives of 75 people. After those fires, the government had promised to improve fire safety at institutions for psychiatric patients.
The fire started in a section of the home dedicated to patients who were unable to walk, emergency services official Igor Kobzev said on Russian state television. He said 39 of the patients in the home could not walk.
All of the patients at the Novokhopersky Neuropsychiatric Home were men and those who died were aged between 46 and 78, according to a list released by the emergency services. Those who were evacuated were placed in a nearby home for elderly and disabled people.
"They carried out 18 people who were sleeping and under the effects of strong medication," he said.
Russia has a poor fire safety record with about 12,000 fire deaths reported in 2012. By comparison, the U.S., with a population roughly double Russia's, recorded around 3,000 fire deaths in 2011.
"The mass death of socially vulnerable people occurs each time for the same reason: a lack of funding, dilapidated buildings and too few personnel, especially on night duty," said Vladimir Markin, a spokesman for the federal investigative agency.
Markin said Russian society should demand the construction of major rehabilitation centers with comprehensive safety systems.
