Dozens dead as powerful tornadoes hit US state of Kentucky

The Kentucky governor has said he was "now certain" that the death toll has surpassed 70 from the powerful tornadoes that swept through his state overnight.

"We were pretty sure that we would lose over 50 Kentuckians," he said in a news conference from the hard-hit town of Mayfield on Saturday. 

"I'm now certain that that number is north of 70. It may in fact end up exceeding 100 before the day is done."

A handful of deaths were also reported in four other states.

READ MORE: Tornadoes kill at least three in Missouri

Roof collapses at Amazon warehouse

In Illinois, authorities said around 100 people were trapped after a roof partially collapsed at an Amazon.com Inc warehouse near St. Louis late on Friday after tornadoes and strong storms blew through the area.

"Our Illinois State Police and Illinois Emergency Management Agency are both coordinating closely with local officials and I will continue to monitor the situation," Illinois Governor JB Pritzer said.

In a statement sent to local media, Amazon spokesperson Richard Rocha said "the safety and well-being of our employees and partners is our top priority right now. We're assessing the situation and will share additional information when it's available."

Officials were working through the early hours of Saturday to rescue employees at the facility – a third of which was reduced to rubble – who were on the night shift processing orders ahead of the Christmas holidays.

The Collinsville Emergency Management Agency described it as a "mass casualty incident" with "multiple subjects trapped at Amazon Warehouse". 

Footage shared across US news channels and social media of the Edwardsville Amazon warehouse showed a large part of the facility's roof ripped off while one of the walls had collapsed into the building, with rubble strewn across the site.