Canadian police expect the death toll from a fatal fuel train blast in a small Quebec town to be more than the one person confirmed dead so far, a spokesman said.
The driverless train and 72 tankers of crude oil jumped the tracks in the small town of Lac-Megantic early in the morning and exploded in a massive fireball.
''We have already confirmed one death and we expect there will be others,'' police spokesman Guy Lapointe told a late-night briefing.
He declined to comment on media reports saying anywhere between 40 and 80 people were missing.
The disaster occurred shortly after 1am (4pm, NZ time) when the runaway train with 73 cars sped into Lac-Megantic, a picturesque lakeside town of about 6000 people in the province of Quebec near the border with Maine, and came off the rails.
Witnesses said the town centre, which included bars as well as stores, a library and residential streets, was crowded with weekend partygoers.
Four of the cars were set alight and blew up in a huge fireball that mushroomed many hundreds of metres up into the air. Many of the destroyed buildings were totally flattened.
The eruptions sent local residents scrambling through the streets under the intense heat of towering fireballs and a red glow that illuminated the night sky.
Quebec provincial police Lt. Michel Brunet confirmed that one person had died. He said he could not say how people many were missing. But Industry Minister Christian Paradis, who handles Quebec affairs for the federal government, indicated the death toll was likely to rise.
"I hope there are not too many dead," a clearly shocked Paradis told public broadcaster Radio-Canada. "It's really terrifying. I think the worst is yet to come."
Officials said they had few reports of injured victims, suggesting that people caught up in the blast either died on the spot or managed to escape.
The train was transporting crude oil from North Dakota to eastern Canada, likely to New Brunswick, news that is bound to revive questions about the safest way to carry the oil needed to service North America's economies.
Montreal, Maine & Atlantic, which operated the train, said it had been parked some distance from the town and no one was on board when it derailed.
"We're not sure what happened, but the engineer did everything by the book. He had parked the train and was waiting for his relief ... somehow, the train got released," Montreal, Maine & Atlantic vice president of marketing Joseph R. McGonigle told Reuters.
Fireman said they were spraying cold water on five unexploded tanker cars they said posed a particular danger. Town Mayor Colette Roy-Laroche urged residents to use water sparingly to help the fire services.
The rail tracks pass next to a bar popular with young people. Eyewitness Yvon Rosa said he had just left the bar when he saw the train speeding into the middle of the town.
"I have never seen a train travelling that quickly into the centre of Lac-Megantic," he told French-language broadcaster Radio-Canada, saying he watched as the train hurtled around a bend.
"I saw the wagons come off the tracks ... everything exploded. In just one minute the centre of the town was covered in fire."
Residents told reporters they had heard five or six large blasts. More than 15 hours after the derailment, one rail car was still burning.
"Many parents are worried because they haven't been able to communicate with a member of their family or an acquaintance," Roy-Laroche told Radio-Canada.
CENTRE OF TOWN 'ALMOST DESTROYED'
Police imposed a 1-kilometre security zone around the blast and evacuated about 1,000 people from their homes.
"When you see the center of your town almost destroyed, you'll understand that we're asking ourselves how we are going to get through this event," a tearful Roy-Laroche told a televised news briefing earlier in the day.
Prime Minister Stephen Harper made an initial statement via Twitter: "Thoughts & prayers are with those impacted in Lac Megantic. Horrible news."
Lac-Megantic is part of Quebec's Eastern Townships region, an area popular with tourists that is close to the border with Maine and Vermont. Quebec is a predominantly French-speaking province in the eastern half of Canada.
Fire officials said they had asked for help from fire services in the United States. Around 20 fire engines were fighting the blaze.
Police said some of the tanker cars had spilled their contents into the river that runs through the town. The Canadian Transportation Safety Board, which probes all accidents, said it was looking for the train's "black box" voice recorder.
Montreal, Maine & Atlantic owns some 820 kilometres of track in Maine and Vermont in the United States and in Quebec and New Brunswick in Canada.
The debate over shipping oil by rail is becoming increasingly topical as President Barack Obama decides whether to approve TransCanada Corp's proposed Keystone XL pipeline from the oil sands of Alberta to the Texas Coast.
Backers of Keystone XL - a project which environmentalists strongly oppose - say transporting oil by pipeline is safer than using rail cars.
There have been a number of high-profile derailments of trains carrying petroleum products in Canada recently, including one in Calgary, Alberta, last week when a flood-damaged bridge sagged toward the still-swollen Bow River. The derailed rail cars were removed without spilling their cargo.