An early morning fire swept through a psychiatric hospital in the Moscow area and killed at least 38 people, including two medical workers, Russian news service RIA Novosti reported.
A nurse was able to lead two patients out of the burning building, sparing their lives, Russia Health Ministry spokesman Oleg Salagay told the news service.
Police said the fire, which began around 3 a.m. local time, was apparently caused by a short-circuit.
Most of the patients died in their sleep from inhaling fumes, police said.
According to Russia Today, a broadcasting outlet, one source told news agencies that the hospital had bars on its windows, preventing people from escaping.