Twenty-two people have been killed and dozens injured by a tornado that hit the US state of Indiana, officials say.
Most of the dead were in a trailer park in Evansville, where mobile homes were devastated by wind speeds estimated to be at least 158 mph (254 km/h).
The tornado is said to have touched down in northern Kentucky before crossing into south-western Indiana at about 0200 local time (0800 GMT).
Weather warnings were issued about 30 minutes before the tornado struck.
Local officials said sirens had sounded but went mostly unheard because it was the middle of the night.
About 200 people were injured, according to the Associated Press news agency.
Thousands of people in the affected areas were left without power.
Eighteen people were killed in the Eastbrook Mobile Home Park in Evansville. said Eric Williams of the Vanderburgh County Sheriff's Department.
Rescuers at the scene reported seeing children wandering around the area looking for their parents, and parents searching for missing children.
"It was just a real loud roar. It didn't seem like it lasted over 45 seconds to a minute, then it was calm again," said Steve Gaiser, who lives near the trailer park.
More people were believed to still be trapped in the debris, and National Guard units were called in to help with search-and-recovery efforts.
Annie Groves, chief deputy coroner for Vanderburgh County, said: "They were in trailer homes, homes that were just torn apart by the storm, so they're just now getting in there trying to find people. It's just terrible."
Four people were killed in neighbouring Warrick County.
Among the places struck was the city of Newburgh, where the top floors were torn off an apartment complex.
The damage path in Newburgh was about three-quarters of a mile (1,200m) wide and 20 miles (30km) long, assistant fire chief Chad Bennett told CNN.
In Henderson County, Kentucky, the Ellis Park racetrack suffered major damage and several horses were killed.
Such a severe tornado is rare in the American Midwest in November, according to the US Storm Prediction Center.
Reuters news agency says killer tornadoes were reported last month in Georgia, Arkansas, Wyoming, Wisconsin and Mississippi, with a total of 10 dead in those storms.
On average tornadoes kill about 70 people a year in the US.
The single deadliest tornado in US history killed 689 people in Missouri, Illinois and Indiana in March 1925, according to the storm prediction centre.