At least 64 people, including six children, died in Kentucky after a raft of tornadoes tore through six US states, with power still out for thousands and strangers welcoming survivors who lost everything into their homes.

While the toll from the deadly twisters was lower than initially feared, Kentucky Governor Andy Beshear said he expected it to increase as searchers continued to sift through a flattened landscape of twisted metal, downed trees and homes reduced to rubble.

“It may be weeks before we have counts on both deaths and levels of destruction,” Mr Beshear said.

The victims ranged in age from five months to 86 years old.

At least 105 people were still unaccounted for as of Tuesday morning (Australian time).

Tweet from @BBCWorld

Mr Beshear said officials were working to confirm that eight people had perished when a candle factory in Mayfield, a town of about 10,000 in the south-western corner of Kentucky, was hit in the storm.

Out of the 110 workers on duty at the Mayfield Consumer Products LLC factory, 94 were believed to have made it out alive, according to the owners of the business, the governor said.

“We feared much, much worse,” Mr Beshear said.

“I pray that it is accurate.”

Aerial shots show the devastation left behind when homes were flattened. Photo: Getty

In the hard-hit small town, the tornado destroyed not only the candle factory but also the police and fire stations.

Homes were flattened or missing roofs, giant trees uprooted and street signs mangled.

Kentucky’s emergency management director Michael Dossett, also at the briefing, said 28,000 homes and businesses remained without power.

Tweet from @TheOrdonezTimes

More than 300 National Guard personnel and scores of state workers were distributing supplies and working to clear roads so that mountains of debris can be removed in the aftermath of the disaster, the governor said.

He said authorities were co-ordinating an “unprecedented amount of goods and volunteers,” and US President Joe Biden was expected to visit the state.

Mr Beshear, at times chocking up, said the search, rescue and recovery process following the destruction had been an emotional roller-coaster for all those involved, including him.

“You go from grief to shock to being resolute for a span of 10 minutes and then you go back,” he said.

Mr Biden had earlier declared a major federal disaster in Kentucky, paving the way for additional federal aid.

While Kentucky was hardest hit, six workers were killed at an Amazon warehouse in Illinois after the plant buckled under the force of the tornado. They included a cargo driver who died in the bathroom, where many workers told Reuters they had been directed to shelter.

A nursing home was struck in Arkansas, causing one of that state’s two deaths.

Four were reported dead in Tennessee and two in Missouri.