A fire at the home for the elderly near Tula, 200 km (120 miles) south of Moscow, engulfed 1,700 sq m of home space and was extinguished in five hours. Hundreds of people were evacuated.
"The casualty toll, according to latest reports, has reached 23 people," Viktor Beltsov said. "The bodies are being identified, and the cause of the blaze is under investigation."
Prosecutors are investigating into possible violations of fire safety rules and negligence at the retirement home. A local police source said a short circuit could have caused the fire.
In a similar incident in June, at least 10 people were killed and four seriously injured in a fire at a retirement home in West Siberia.
Sixty-one retirees and medical personnel died in a fire at a retirement home in the Krasnodar region in southern Russia in March. Last December, 46 patients at a Moscow drug treatment clinic died in a fire. And at least nine students died and dozens were injured in a blaze at a Moscow dormitory last October.
