A desperate search for survivors is being carried out in six US states battered by a series of devastating tornadoes that have left at least 83 people dead.
Dozens more people are missing and entire towns were destroyed by as many as 30 tornadoes that wreaked havoc on Friday.
U.S. President Joe Biden on Saturday approved an emergency declaration for Kentucky, the worst-affected state where more than 70 people have died, including dozens in a candle factory. The death toll is expected to rise above 100.
Biden has ordered federal aid to supplement the response from state and local authorities, the White House said.
"It's a tragedy. And we still don't know how many lives were lost and the full extent of the damage," Biden told reporters.
Asked if he thought climate change played a role in the devastation of the storms, Biden said he would be asking the Environmental Protection Agency and others to take a look.
"Acknowledging that the likelihood of fewer weather catastrophes, absent a continued movement on dealing with global warming, is just not going to happen," he said.
Biden also said a longer-term question, beyond the immediate response, sparked by the disaster for the states and the nation would be about the tornado warning systems.
Weather forecasters said the storms are unusual for this time of the year.
According to a BBC report, 40 people have been rescued from the collapsed candle factory in Mayfield but 60 more remain missing and Kentucky Governor Andy Beshear, who has visited the scene, said it was unlikely there were more survivors.
"There's at least 15ft of metal with cars on top of it, barrels of corrosive chemicals that are there. It'll be a miracle if anybody else is found alive in it," he said.
One candle factory employee made a desperate plea for help on Facebook from under the wreckage as co-workers could be heard moaning in the background.
"We are trapped, please, y'all, get us some help," said Kyanna Parsons-Perez – who was later rescued – in the broadcast played on CNN.
Mr Beshear said the tornado had wrecked places all along its 227-mile (365km) path, including the town of Dawson Springs.
"One block from my grandparents' house, there's no house standing and we don't know where all those people are," he said.
Local congressman James Comer, working with rescuers in the ruined town of Mayfield, said the tornado there was the widest ever seen.
