President Barack Obama is to visit storm-ravaged communities in Alabama as south-eastern US states face up to the aftermath of devastating storms.
At least 297 people are known to have died from tornadoes that ripped through a swathe of states, 204 in Alabama.
Mr Obama will visit Tuscaloosa, Alabama, where a twister thought to be a mile wide ploughed through the city.
He has pledged government support for storm-hit communities, with federal aid money being sent to Alabama.
Deaths and widespread devastation are also reported in Tennessee, Mississippi, Georgia and Virginia.
On Thursday the president hailed rescue workers and said he stood with every American affected by the "catastrophic" storms.
A state of emergency has been declared in seven states, and federal aid money is being sent to Alabama.
‘Reeling’
Speaking at a news conference at the White House, Mr Obama said: "The loss of life has been heartbreaking, especially in Alabama.
"In a matter of hours, these deadly tornadoes, some of the worst we have seen in decades, took mothers and fathers, sons and daughters, friends and neighbours, even entire communities.
Confirmed deaths by state
- Alabama: 210
- Mississippi: 33
- Tennessee: 33
- Georgia: 15
- Virginia: 5
- Kentucky: 1
Source: Associated Press, BBC reporting
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"In many places the damage to homes and businesses is nothing short of catastrophic," he said.
The president said he would travel to Alabama to meet those leading the emergency response and families who are "reeling from the disaster".
"I want every American who has been affected by this disaster to know that the federal government will do everything we can to help you recover, and we will stand with you as you rebuild," he said.
The US National Weather Service has reports of nearly 300 tornadoes since the storms began on Friday, more than 150 of them on Wednesday