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Investigators were trying to pick through the icy rubble of a charred seniors' facility in Quebec Friday to try to identify more victims of a fire that killed at least five and left about 30 missing. The home for the elderly now resembles a macabre frozen palace, with sheets of ice and thick icicles covering the destroyed structure.

Canada's prime minister said there was little doubt the death toll would climb in the eastern Quebec town of L'Isle-Verte, where sub-freezing temperatures have hampered the recovery effort. The cause of Thursday's early morning blaze remains unclear.

Witnesses told horrific tales of seeing people die in the blaze. Most of the residents probably never had a chance to escape -- many of them were over 85, had little or no mobility and were confined to wheelchairs or walkers.

Pascal Fillion said he saw someone use a ladder to attempt to rescue a man cornered on his third-floor balcony. The man was crying out for help before he fell to the ground engulfed in flames.

A Quebec Health Department document indicates the residence, which has operated since 1997, had only a partial sprinkler system. The facility expanded around 2002 and the sprinklers in the new part of the building triggered the alarm.

Fire Chief Yvan Charron said his colleagues were able to get to the portion of the building that remained standing, while the rest remained inaccessible.

The massive fire in the three-story building erupted at about 12:30 a.m. Thursday and quickly spread. Firefighters arrived within eight minutes of getting the alarm and several fire departments in the region were called in to help. But they were unable to carry out a complete evacuation because of the fire's intensity.

About 20 residents were transported to safety.

The fire broke out in -4 Fahrenheit temperatures, causing equipment to freeze, Charron said. The search for the missing has been hampered by the cold and thick ice and the building's collapse, said Quebec Provincial police Lt. Guy Lapointe. Investigators initially had hoped to work through the night but were unable to because of the thick ice and fire beneath the rubble.

Agnes Fraser's 82-year-old brother, Claude, was among the missing, but she said she knew she would never see him again because he lived in the section of the building destroyed by the flames.

"It's done," Fraser said.

The fire comes just six months after 47 people were killed in Lac-Megantic, Quebec, when a train with 72 oil tankers derailed and exploded in the small community.

In 1969, a nursing home fire in the community of Notre-Dame-du-Lac, Quebec, claimed 54 lives.