Raging wildfires pressed in on the Canadian oil city of Fort McMurray Thursday after more than 80,000 people were forced to flee, abandoning fire-gutted neighborhoods in a chaotic evacuation.

No casualties have been reported from the monster blaze, which swept across Alberta's oil sands region driven by strong winds and hot, dry weather.

But authorities warned that the next 24 hours would be critical for the city's survival.

Meanwhile mandatory evacuation orders were issued for two other Alberta towns -- High Level, home to 4,000 people about 350 kilometers (220 miles) northwest of Fort McMurray, and Lac Ste Anne, a community of several hundred people about 100 kilometers (60 miles) east of Edmonton, the provincial capital. The alert was later lifted in Lac Ste Anne.

In Fort McMurray, the fires late Wednesday forced the evacuation of Saprae Creek, a neighborhood east of the city's airport that until now had been out of danger. Even its fire station was pulled out.

"This fire is absolutely devastating," said Prime Minister Justin Trudeau. "It's a loss on a scale that is hard for many of us to imagine."

The flight from Fort McMurray began in earnest shortly before midnight Tuesday when the Alberta emergency services placed the city of 100,000 under a mandatory evacuation order.

Footage showed trees ablaze near highways crowded with bumper-to-bumper traffic, while black smoke billowed as the flames ate away at buildings.

Mayor Melissa Blake said predictions of what would happen not only came true but were worse than imagined.

"This is a very explosive situation," warned Bernie Schmitte of Alberta's agriculture and forestry ministry. "These are catastrophic wildfires."

The fire has destroyed some 2,000 residences in the city's most outlying districts and ravaged 10,000 hectares (25,000 acres), he said.

More than 80,000 have fled the city, located 400 kilometers north (250 miles) of the provincial capital Edmonton, according to Scott Long of Alberta's emergency management agency. The area around the airport is the only one not under an evacuation order.

Warning that the next 24 hours were critical, Schmitte launched an urgent appeal to the population as firefighters noted that winds were fanning the flames in various parts of the city.

"We are going to ask you to stay where you are so that we can utilize all roads," he said.

Nine air tankers, a dozen helicopters and some 250 firefighters were battling the flames, and the military was put on alert.

"Obviously, Fort McMurray being evacuated has been extremely difficult, not just for the province and officials, but for the folks who live there," Trudeau said.

The prime minister added he had spoken with Alberta Premier Rachel Notley and offered her "our total support as a government to anything needed in the short-term but obviously anything in the long-term."

Notley said that no casualties had been reported, noting that everything possible was being done to ensure the population's safety.

"I believe at this point we have the resources that we need and we are continuing to work very hard to get the fire under control," Notley told a news conference, adding that "the view from the air is heartbreaking."

Since 8:00 am (1400 GMT) Wednesday, flights to the city have been suspended.

- Wind fans flames -

Oil companies crucial to the region such as Suncor, Syncrude and Shell reduced operations to facilitate the evacuation of non-essential employees.

Public Security Minister Ralph Goodale, working in connection with the armed forces, said "a number of federal air assets are now positioned in the neighborhood" to help with evacuation.

The fire, which had been contained until Monday south of Fort McMurray, was pushed toward the city by winds of 50 kilometers per hour and quickly reached homes, helped by a drought in Alberta.

The province saw record temperatures of nearly 30 degrees Celsius (86 Fahrenheit).

The evacuation has caused huge traffic jams, especially around gas stations where some drivers waited hours to fill their tanks. With some pumps in the 400 kilometers between Edmonton and Fort McMurray to the north empty, the Alberta government has said it sent a tanker under guard to help rescue stranded vehicles.

- Charred cars -

The authorities said the inferno had reached the neighborhood of Beacon Hill, only five kilometers from downtown Fort McMurray.

Seventy percent of homes there had been destroyed, they said.

In the Waterways neighborhood, 90 percent homes have been lost.

Firefighters said houses had been damaged in all Fort McMurray neighborhoods and that numerous empty vehicles near wooded areas had gone up in flames.

A large motor home park had also been destroyed, leaving charred and smoldering remains, according to TV footage.

Oil companies had set up emergency shelters in their huge bungalow communities for Canadian and foreign workers.

These camps have been partially deserted for the past two years due to the drop in oil prices and the thousands of layoffs that followed.

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ROYAL DUTCH SHELL PLC

SUNCOR ENERGY