Rescue teams in eastern Alabama have resumed search operations a day after two tornadoes caused extensive damage to buildings and roads.
At least 23 people are known to have died in Lee County, some of them children, with the youngest believed to have been six years old.
There are fears that the death toll will rise. Dozens of people were hurt.
The sheriff of Lee County, Jay Jones, told local media that the devastation caused by the winds was “incredible”.
He said: “It looks like someone has taken a giant knife and scraped the ground. There are slabs where homes formally stood, debris everywhere… whole forested areas with trees are snapped and lying on the ground… a lot of devastation out there.”
Nearly 2,000 homes in the affected area are without power following the tornadoes.
A state-wide state of emergency is in operation, with resources from across the state pouring into the affected area. Drones with infrared capability are being used in an attempt to find survivors.
Rescue efforts were halted overnight because of the dangers associated with searching in the dark.
The area around Beauregard, about 60 miles (95km) east of Alabama’s state capital Montgomery, appears to have borne the brunt.
The tornadoes there struck at about 14:00 (20:00 GMT) on Sunday, carving a path at least a half a mile wide and at least a mile long.
Footage of the aftermath shows snapped communications poles, roads littered with debris and wrecked houses.
The National Weather Service (NWS) made a classification of at least EF-3 – meaning winds of up to 165mph (266km/h).
Local resident Scott Fillmer said: “Everything just kind of went dark, when it was almost like night outside. And it’s that old cliché that it sounds like a freight train coming, well that’s what it sounded like.”
Residents of Smiths Station told local TV they had seen businesses destroyed there. A large bar called the Buck Wild Saloon had its roof torn off.
Tornado warnings were also issued for Georgia, Florida and South Carolina. Footage showed smashed buildings and snapped trees in Talbotton, about 80 miles south of Atlanta.
Tornadoes were also reported in Walton County and Cairo in northern Florida.
All of the deaths reported so far have been in Lee County. Authorities say they are still working to identify the victims and the injured. -BBC