Thirty-eight people, mostly psychiatric patients, were killed Friday in a fire that ravaged a hospital in the Moscow region, with the victims engulfed by flames as they slept behind barred windows.
The deadly nighttime blaze raised new questions about security standards at Russia's medical institutions, in particular psychiatric hospitals, after a string of fires in the last years.
The fire broke out on the roof and spread rapidly throughout the hospital wing in the small town of Ramensky around 40 kilometres (25 miles) outside Moscow, the health ministry said.
Officials said the residents of the hospital wing were burnt to death or suffocated while they slept as the fire spread rapidly through the wooden building, although three managed to escape in the early stages of the inferno.
"According to preliminary information, 38 people died, three survived -- one staff medic and two patients," the health ministry said in a statement.
The emergency situations ministry listed those believed to have died as two female members of staff and 36 patients.
The ministry said the first report of the fire was at 2:00 am (2200 GMT) and the blaze was localised two hours later. However it took the fire services over an hour to reach the site, instead of the standard 20 minutes.
The cause of the fire is still under investigation.
"Thirty-six bodies have been recovered. Of these, only seven were poisoned by carbon monoxide, the rest have burns," the spokeswoman for regional investigators, Irina Gumyonnaya, told the RIA Novosti news agency.
Acting regional governor Andrei Vorobyov told Rossiya 24 television that "the investigation must decide whether the (window) bars were the reason or not" for why so few were able to flee to safety.
The patients slept soundly as they had taken medication in the evening, the ITAR-TASS news agency reported, citing a spokesman for the rescue operation.
The smoke alarms did activate in the hospital and woke a nurse who managed to save two patients, the rescue operation spokesman said.
"When the nurse came out into the corridor, the fire was burning and the flames were spreading quickly. She managed to bring out only two patients: a woman and a young man," the spokesman said.
According to the list released by the emergency situations ministry, the ages of the victims varied widely with several patients in their 70s but others only in their 20s.
The youngest victim appeared to be a female patient named Lyubov born in 1993.
The institution's chief doctor, who was not named by Russian media, described the patients as a "very tough group of people -- psychiatric patients with chronic illnesses and frequent attacks" who suffered from alcohol and drug addiction.
Russia's Investigative Committee said in a statement it had opened a criminal probe into a failure to observe fire security regulations, causing multiple deaths.
It named as possible causes careless handling of fire or a short circuit in the electric wiring, but also gave arson as a possibility.
The chief doctor was quoted as saying the one-storey building was entirely wooden and dated from 1952.
Firefighters took over an hour to reach the clinic because a road crossing over the nearby canal was closed, a spokesman for the emergency situations ministry told the Interfax news agency.
The Moscow region announced a day of mourning to be held on Saturday and compensation of 500,000 rubles ($16,026, 12,275 euros) for each family.
The fire was the latest tragedy to hit a medical institution in Russia, which still suffers from outdated Soviet-era infrastructure and lax security procedures.
In 2009, 23 people died in a blaze in the wooden building of a home for the elderly in Komi republic in northern Russia while in 2007, 63 died in a fire at an old people's home in the southern Krasnodar region.
In 2006, a fire in a Moscow drug rehabilitation clinic killed 45 women. Many of the victims were trapped by metal bars on the windows that staff could not open and an emergency exit was boarded up, officials said.