Dangerous conditions are hampering the search for 40 people still missing since a runaway crude-oil train blew up in a Canadian town early on Saturday local time.
Police say the death toll has risen to 13 with the discovery of eight more bodies, and they estimate a total of about 50 people are either dead or missing.
The BBC reports police are still unable to examine much of the devastated area because dozens of tanker wagons loaded with oil remain strewn across the site in the centre of the Quebec town of Lac-Megantic.
At least 30 buildings were incinerated by the fireball and eyewitnesses say the streets were "filled with fire". Canadian prime minister Stephen Harper said the place looked like "a war zone" when he toured the area on Sunday.
Many of those missing are thought to have been drinking at a popular downtown bar when the explosions occurred.
Anne-Julie Huot, 27, says at least 25 people she knows are still missing. "I have a friend who was smoking outside the bar when it happened and she barely got away, so we can guess what happened to the people inside."
One man who escaped from the bar told CBC he had not been able to sleep because he keeps hearing the screams of his friends.
None of the dead have been identified, and the five bodies recovered so far, all badly burned, are being sent to Montreal for identification. Officials have warned that some of the dead may never be recovered, given the intensity of the fire.
How did it happen?
The train, operated by Montreal, Maine & Atlantic Railway, had been on its way from the Bakken Field in North Dakota to a refinery in St John, New Brunswick. It had been parked in the village of Nantes, about seven kilometres from Lac-Megantic, during an overnight driver shift-change on Friday evening.
Firefighters from Nantes were later called to put out a small fire on the train, and sometime afterwards, 73 wagons carrying pressurised containers of crude oil became uncoupled from five locomotive engines. Gathering speed, they hurtled downhill before derailing in the heart of Lac-Megantic.
Montreal, Maine & Atlantic chair Ed Burkhardt says the airbrakes that would have prevented the disaster failed because they were powered by an engine that had been shut down by the firefighters. He says the engine needed to keep running in order for the airbrakes to continue working.
Canada's transportation safety board has retrieved the train's data recorder and a separate device that contains details of the braking system.
Ed Burkhardt had a high profile in New Zealand during the 1990s, when a company he helped found, Wisconsin Central, became involved in the privatisation of the national rail network. He is New Zealand's honorary consul to the Canadian mid-west.