A desperate search for survivors is underway in parts of six U.S. states devastated by powerful tornadoes that have left at least 94 people dead.
Dozens more people are missing and entire cities were destroyed by about 30 tornadoes on Friday.
President Biden has declared a disaster in Kentucky, the worst-hit state.
At least 80 people have died in the state, including dozens in a candle factory, and the death toll is expected to rise above 100.
Kentucky’s lieutenant governor Jacqueline Coleman told the BBC that the death toll continues to rise “for every hour”.
“All these numbers keep unfolding …,” she said. “Our emergency response team is still investigating the damage and knocking on doors and reaching out to people trying to make contact to see who is alive.”
Local Congressman James Comer, who works with rescuers in the devastated city of Mayfield, said the tornado there was the widest ever seen.
“It’s the most devastating storm damage I’ve seen in my entire life. We’ve had tornadoes that have been the same length as this tornado, but we’ve never had one with the width of this tornado,” he said.
Forty people have been rescued from the collapsed candle factory in Mayfield, but 60 more are missing, and Kentucky Governor Andy Beshear, who has visited the site, said it was unlikely there were more survivors.
He said no one had been found alive since Saturday.
“There is at least 15 feet of metal with cars upstairs, barrels of corrosive chemicals that are there. It will be a miracle if anyone else is found alive in it,” he said.
A candle maker was desperately asking for help on Facebook from under the wreck as colleagues could be heard moaning in the background.
“We’re trapped, thank you, I’all, get us some help,” Kyanna Parsons-Perez – who was later rescued – said in the broadcast played on CNN.
Mayfield resident Tony Meeker described the moment the tornado hit.
“Out of nowhere the sirens went, and not long after our ears fluttered. I mean, it was as if the pressure was dropping. And then it felt like our house was about to be gone, being carried away,” he said.
“It looks like a bomb went off. I do not know how anyone could have lived. I feel sorry for someone who did not reach it, or people who were stuck. I’m sure it was scary.”
Sir. Beshear said the tornado had destroyed places along its 227-mile (365 km) trail, including the town of Dawson Springs.
“A quarter of an hour from my grandparents’ house there is no house and we do not know where all those people are,” he said.
Tornadoes also collapsed an Amazon warehouse in Edwardsville, Illinois, killing six people. Police say it is still unknown how many workers are missing. Amazon founder Jeff Bezos said he was “crushed” and promised support to the community.
Sir. Biden has signed a federal emergency declaration releasing funds to Kentucky. He said the loss of human life caused by the tornadoes was a “tragedy”.
Tens of thousands of people in the state lack electricity and water.
By Nomia Iqbal, BBC News, Bowling Green, Kentucky
The destruction is extraordinary to see. The strong series of storms tore through a neighborhood of Bowling Green in southern Kentucky.
Dozens of homes are severely damaged or completely destroyed. Power lines hang loosely on the roads and whole trees are uprooted. Toys, books, clothes are scattered across people’s lawns.
In one home, half of the roof collapsed in the garage, burying the owner’s car. A man approaches the battered front door with his children and looks inside. His 97-year-old aunt lives inside, he says, and he can not get hold of her.
“We’re worried. She does not have a cell phone or anything,” he says. “God, I hope she came out safe and sound.” A few minutes later after talking to a relative on the phone, relief spreads across his face. “She was in the bathtub, but came out safely. She’s fine. She’s fine.”
Further down the street, a nearby gas station has been decimated and a single pumping station stands in the courtyard. A large air conditioner that would normally sit on top of the kiosk has come completely off the roof and blown over on the other side of the road.
As the sun goes down over the city, it is eerily quiet. The only noise and light comes from the nearby police cars patrolling the area.
Other incidents in Kentucky included a train derailment during extreme winds in Hopkins County. One train car was blown 75 m up a hill and another landed on a house. No one was injured.
Local officials also described how two children were reported missing during a tornado but were later found alive in a bathtub that had been pulled outside by the force of the wind.
Four people were killed in Tennessee, local officials said. Two people were killed in Arkansas, one of them in a nursing home, after it partially collapsed. One death was confirmed in Missouri.
The intensity of the recent storms has prompted speculation about how much they have been affected by climate change, although President Biden said the exact effect was not yet clear.
“We all know that everything is more intense when the climate warms, everything,” he said.
The longest a tornado has traveled along the earth in the United States was a 219-mile storm in Missouri in March 1925 that claimed 695 lives.
However, such large events outside the spring and summer months are extremely rare.