Kentucky’s governor Andy Beshear broke down in tears on Monday as he announced the deaths of at least 64 people from Friday’s deadly tornadoes that swept across multiple midwest and southern states, and warned that the death toll is expected to grow.

The ages of those killed ranged from five months to 86 years, six of them younger than 18, Beshear said at an emotional press conference in Frankfort, the state capital.

He said that 105 Kentuckians were still unaccounted for, and that the eventual number of confirmed deaths might not be known for weeks.

“We believe it’ll certainly be above 70, maybe even 80,” he said, his voice faltering. “I know, like the folks of western Kentucky, I’m not doing so well today. And I’m not sure how many of us are.”

Crews continued to sift the devastated ruins of towns across multiple states on Monday as many grieved and survivors shared harrowing tales of their escape.

Kentucky was the worst hit of eight states where dozens of tornadoes whirled through in massive nighttime storms that leveled whole communities.

Joe Biden declared a major federal disaster in Kentucky, where representatives of a candle factory in the small city of Mayfield reduced to eight the number they said were still unaccounted for. Another eight of 110 shift workers are known to have died after an unseasonal, record-breaking tornado with whirling winds up to 200mph razed the building.

The US president plans to visit Kentucky on Wednesday.

“There were some early reports that as many as 70 could be dead in the factory. One is too many, but we thank God that the number is turning out to be far, far fewer,” said Bob Ferguson, spokesperson for Mayfield Consumer Products that owns the facility.

Beshear said authorities were working to confirm the figures.

As rescuers continued to search the wreckage in Mayfield and across the state, thousands remained without power and water, or homeless.

“The state was hit by at least four tornadoes. One stayed on the ground in Kentucky for at least 200 miles, devastating anything in its path. Thousands of homes are damaged, if not entirely destroyed,” Democrat Beshear said.

“We’re going to keep putting one foot in front of the other [and] push through this. We’re not going anywhere. We’re going to be with you today. We’re going to be with you tomorrow. And we’re going to be there with you to rebuild,” he said.

More than a dozen additional deaths are confirmed in total so far across Arkansas, Illinois, Missouri and Tennessee, including at least six who were killed in a destroyed Amazon warehouse in Edwardsville, Illinois.

“It sounded like a train came through the building. The ceiling tiles came flying down. It was very loud,” warehouse worker David Kosiak, 26, said. “We were in the bathrooms. It was at least two and a half hours in there.”

Outside a wrecked apartment complex in Mayfield, Kentucky, residents spoke of being trapped in the debris for hours, and crying for help as they tried to escape.

Johnny Shreve watched from his window as an office structure across the street disintegrated, then dived onto his kitchen floor as the tornado hit his building and chunks of concrete pelted his body.

“It felt like everything in the world came down on me,” he said.

He lay there for an hour, trying to dig himself out and shouting for his neighbors and his dog. Eventually he broke through into the living room and found the dog trying to scratch toward him from the other side.

He posted on Facebook that they were alive, and added: “Y’all pray for Mayfield.”

“It blew my mind when the sun came up,” Shreve said, when he and others returned to salvage what they could and trade stories of survival.

“I don’t see how this town can recover. I hope we can, but we need a miracle.”

A local pastor, Joel Cauley, described the scene at the candle factory. “It was almost like you were in a twilight zone. You could smell the aroma of candles, and you could hear the cries of people for help,” he said.

“Candle smells and all the sirens is not something I ever expected to experience at the same time.”

The factory was reduced to 15-ft deep wreckage of twisted metal, with corrosive chemicals spilled everywhere and smashed cars on top, where the roof had been, all leaving a difficult and dangerous site at the county’s largest employer.

Wanda Johnson, 90, a resident of an apartment block in the nearby town of Wingo, spoke of her windows “bursting” and how she clung to a door frame in an effort to avoid being blown away. “Dear God, help me, please help me get out of here,” she recalled saying.

Speaking from a shelter beside her son and granddaughter, Johnson said: “They tell me we don’t have a town. Everything’s gone. It’s just wiped away. It just flipped over our city.

“We don’t know where we’re going to go. We don’t know what’s left to go to.”

More than 100 others were in the shelter with Johnson. Aid agencies have set up similar facilities in churches, school gymnasiums and community halls across Kentucky and elsewhere to provide warmth, food and clothing.

Michael Dossett, director of Kentucky’s division of emergency management, said national guard troops and other agencies were bringing in generators. Power restoration in some areas “will be weeks to months,” he said, amid nighttime temperatures below freezing, while other area communities faced a longer recovery time.

“This will go on for years to come,” he said. “This is a massive event, the largest and most devastating in Kentucky’s history.”

Weather experts, meanwhile, were analysing the unprecedented nature and severity of the storms, which spawn most tornadoes in the spring, not December.

More than 80 tornadoes were reported in eight states, prompting Biden to ask the US environmental protection agency to investigate what role the climate crisis might have played.