Photo taken on Dec. 11, 2021 shows a heap of rubble after tornadoes in Mayfield, Kentucky, the United States.Photo:Xinhua

Kentucky officials voiced relief Monday that dozens of workers at a candle factory appear to have survived tornadoes that killed at least 88 people and left a trail of devastation across six US states. 

Governor Andy Beshear said 74 deaths have been confirmed in the southeastern state and choked up as he told reporters the fatalities ranged in age from 5 months old to 86.

"Like the folks in western Kentucky, I'm not doing so well today and I'm not sure how many of us are," Beshear said.

The governor said 109 people in Kentucky remain unaccounted for and "it may be weeks before we have final counts on both deaths and levels of destruction."

But the governor said fears of a devastating death toll in the collapse of the candle factory in the ravaged town of Mayfield were apparently unfounded.

Some 110 employees were working late Friday at the Mayfield Consumer Products plant to meet the holiday rush when a twister ripped the building to shreds.

Jemaryon Hart, 21, said "I'm happy I'm alive" after surviving a grueling seven hours trapped under the rubble of the factory.

"It was really scary, really painful, the walls, cinder blocks, metal, wood, everything just crushing you," he told AFP.

The factory owners reported eight dead and eight missing from the collapse, and said "94 are alive and have been accounted for," Beshear said.

"We are working on verifying the information from the candle factory that right now would only have eight confirmed dead, which is a Christmas miracle we hoped for, but we have to make sure it's accurate," Beshear said. "We feared much, much worse."

Thousands of people have been left homeless by what the governor described as the state's worst storm on record.

Fourteen deaths have been reported in four other states hit by the twisters - Tennessee, Arkansas, Missouri and Illinois. There was also damage, though no deaths, in Mississippi.

Six people were killed at an Amazon warehouse in the southern Illinois city of Edwardsville, where workers were on the night shift processing orders ahead of Christmas.

President Joe Biden said he will visit Kentucky on Wednesday and survey damage in Mayfield.

"It's just devastating," Biden told reporters, holding up photographs of the town. 

"It's a town that has been wiped out. But it's not the only town."

Biden has declared a major disaster in Kentucky, allowing additional federal aid to be channeled into recovery efforts.

A massive search effort was underway on Monday at the candle factory, which was left a twisted ruin by the force of the powerful winds.

A crane was methodically removing parts of the collapsed roof and rescuers accompanied by sniffer dogs were searching the debris by hand.

AFP