At least 50 people were likely "killed" after multiple tornadoes swept through the U.S. state of Kentucky, state Governor Andy Beshear said on Saturday.

"We believe our death toll from this event will exceed 50 Kentuckians, probably end up closer to 70 to 100 lost lives," Beshear said at a briefing on the storm damage and the state's response.

"It has been one of the toughest nights in Kentucky history," Beshear said. "Some areas have been hit in ways that are hard to put into words."

Calling the storms that hit the state "the most severe tornado event in Kentucky's history," Beshear declared an official state of emergency.

At least 24 tornadoes were reported across five states, including Arkansas, Illinois, Kentucky, Missouri and Tennessee, according to the National Oceanic and Atmospheric Administration (NOAA) Storm Prediction Center, with fatalities also being reported by officials in Arkansas and Illinois, said CNN.

Around 100 people were trapped when a roof partially collapsed at an Amazon.com Inc warehouse near St. Louis after tornadoes and strong storms roared through the area, local media reported.

(With input from agencies)