Powerful tornadoes have swept through the US Midwest, destroying buildings and overturning vehicles in the states of Illinois, Indiana and Kentucky.
At least five people were killed and it is feared that several hundred people may have been injured in the fast-moving storms. A number of people are said to be trapped inside buildings.
Forecasters say up to 53 million people could be affected. Hailstones the size of tennis balls have been reported, the BBC reports.
The rapid-moving storm - with winds of up to 111km/h was continuing its way east on Sunday.
November is usually one of the quietest months in the tornado calendar, meaning these storms are unusually destructive for this time of year.
One person died in the town of Washington, Melanie Arnold of the Illinois Emergency Management Agency was quoted as saying. An elderly man and his sister were killed when a tornado struck their farm house in the village of New Minden.
Illinois officials are describing the situation as "dangerous and volatile".
Karen Harris, a food truck operator in Washington, told the BBC she saw a "car completely mangled, the houses gone".
"Telephone wires [are] down everywhere, live wires are still down. I'm pretty traumatised from what I saw.
"I actually saw a vehicle in the middle of the road, their left signal light turned on, like they were getting ready to turn, all the windows were out of it, blood was in the back seat. Pandemonium. It looks like a war zone."
Fears that the storm could hit Chicago forced the evacuation of American football fans from the city's stadium.
The National Weather Service warned of a "particularly dangerous situation" for parts of the central United States.