At least 38 people died early Friday in a fire at a psychiatric hospital near Moscow, the Russian Health Ministry said.
The blaze tore through the hospital, killing 36 patients and two staff members, officials said.
The fire was out and Andrei Vorobyov, acting governor of the Moscow region, had rushed to the scene.
A criminal investigation was launched and Saturday will be a day of mourning, the health ministry said.
The fire may have been sparked by an electrical short, the state-run news agency RIA Novosti reported.