At least 13 people were killed and an estimated 37 others are still missing in the small town in Quebec where a runaway train exploded Saturday, Canadian police said at a news conference on Monday.
Investigators last reported 40 missing and five dead on Sunday. Police are counting as missing people whom direct family members have reported, Quebec provincial police spokesman Benoit Richard said.
"Hot zones" lingering more than two days after the train derailment in Quebec were hampering authorities' efforts to continue their search for missing people.
The unmanned train was carrying 72 tankers of crude oil when it plowed into the heart of Lac-Megantic, Quebec, on Saturday. The crash and a series of explosions flattened 40 buildings and forced nearly 2,000 people to evacuate the town, 130 miles east of Montreal.
More than 1,500 of those evacuated will be allowed to return to their homes Tuesday, officials said.
Among the buildings destroyed was the Musi-Cafe, which was hosting live music the night of the crash. Authorities have said they suspect some of the 40 missing residents were at the popular bar that night.
"There's been a lot of work that's been done on the scene during the night and hopefully we'll get some more areas we can search during the day, but that, of course, is under the firefighters' responsibility," Richard said.
Sunday, provincial police Lt. Michel Brunet said at least five burned bodies had been found, but "we know that there will be many more" deaths.
Canadian Prime Minister Stephen Harper described the town as a "war zone."
"There is not a family in this area that is not touched by this," Harper told reporters after touring the destruction Sunday.
Canadian Transport Minister Denis Lebel said officials are working to find out whether any safety violations contributed to the crash, and said he would take "immediate action" if so.
How did it happen?
The company responsible for the train said that after the crew parked the locomotive for the night at a station about seven miles from Lac-Megantic, the air brakes holding the train in place likely failed, allowing the train to barrel downhill into the town.
The Montreal, Main & Atlantic Railway said the investigation is continuing.
"We don't know if the brakes were properly applied to the train, and we haven't been able to get into the fire area in order to inspect," Edward Burkhardt, president and CEO of Rail World Inc., the railway's parent company, told CTV.
Investigators with the Transportation Safety Board of Canada found the locomotive event recorder, which they can analyze for information on throttle position and speed, among other data.
The Quebec disaster came on the heels of a handful of other mishaps involving trains transporting oil in Canada, prompting some in the Canadian government to criticize what they say is a trend allowing rail lines to police themselves.
Among the incidents:
-- Four Canadian Pacific rail cars carrying flammable petrochemicals used to dilute oil derailed on a flood-damaged bridge spanning Calgary's Bow River in June, according to the Calgary Herald.
-- In another incident involving Canadian Pacific, five tankers containing oil derailed in rural Saskatchewan in May, spilling 575 barrels of crude, the Toronto Sun reported.