Media playback is unsupported on your device Media caption The BBC's Beth McLeod: "Many are missing feared dead"

As many as 31 elderly Canadians are unaccounted for and five are confirmed dead after a fire destroyed an old people's home in Quebec.

Prime Minister Stephen Harper said there was little doubt the loss of life at Residence du Havre in L'Isle-Verte would be "considerable".

The blaze was first reported the early hours of Thursday.

Firefighters, who arrived within eight minutes of being called, saw and heard residents they were unable to save.

Many of the residents were users of wheelchairs and walking frames, officials said.

It was "a night from hell", local chief firefighter Yvon Charron told the Canadian Press.

Emergency crews were able to save about 20 of the home's 50-60 residents, three of whom were injured.

'Burned to death'

Firefighters battled the blaze for five hours in temperatures as low as minus 22 Celsius (minus 7.6 Fahrenheit) -- freezing conditions that have continued to hamper rescue efforts.

Officials said they hoped at least some of those unaccounted for had been visiting family.

"We hope for the best," police Sgt Audrey-Annie Bilodeau told reporters.

Several fire departments were called to the town of 1,400 - 225km (140 miles) east of Quebec City - to help extinguish the fire, which was fanned by strong winds.

Most of the residents were over 75 years old, and 37 were over 85 years old. Many were infirm and suffering from Alzheimer's disease, and only five were fully mobile and autonomous, L'Isle-Verte's acting Mayor Ginette Caron told reporters.

"All our thoughts are with the families, the people affected by this ordeal," Ms Caron said.

Image copyright AFP Image caption Residence du Havre was in the centre of the small town north-west of Quebec City

Witnesses described scenes of horror, watching the building burn and knowing elderly residents were trapped inside.

Mario Michaud, who lives across the street, told the local newspaper Info Dimanche he watched a man try but fail to rescue his mother, who was shouting for help from a second-storey balcony.

"She burned to death," Mr Michaud said.

Image copyright Reuters Image caption More than 30 of the residents were over 85 years old

Another man, Jacques Berube, told the Associated Press he feared the worst for his missing mother, Adrienne Dube, 99 years old and blind.

"I went near the building; the corner where her room was is burned," he said. "I'll just have to wait and see. I don't like it. But I don't have any choice. It's just reality."

Retired police officer Pierre Filion, who had a cousin and an aunt living in the residence and who lives nearby, said the tragedy had shaken the tightly knit community.

"It's going to take a long time to start living normally," said Mr Filion, whose missing relatives are both in their 70s.

Image copyright AFP Image caption As water from fire hoses froze in the -22C temperatures, the building began to look like a macabre ice palace.

Meanwhile, investigators have begun searching for the cause of the blaze.

A recent Quebec health department document suggested that only parts of the building, which was made entirely of wood, had a sprinkler system, but that there were smoke detectors in every room.

Quebec Minister of Labour and Social Solidarity Agnès Maltais told reporters on Thursday the government would consider making sprinklers compulsory.

"We believe [seniors] are well-protected but we always have to tighten the rules each time we see there's a failure somewhere," she said.

"We're waiting for the result of the inquiry… to understand where the failure is."

Jean-Pierre Ouellet of the FTQ labor union told Radio Canada that regulations for seniors' homes were not strict enough.

Image copyright AP Image caption Firefighters battled frigid temperatures in addition to the blaze

Quebec Premier Pauline Marois expressed her sympathy for victims from Davos in Switzerland, where she is attending the World Economic Forum.

"I want to offer my deepest condolences to all the families who have lost someone," Ms Marois said. "My government will do everything it can to help people there."

The worst-ever fire in a Canadian nursing home occurred in Notre-Dame-du-Lac in Quebec, in 1969, when 54 people died.