At least 23 people have died, some of them children, amid “catastrophic” damage from a tornado in Alabama.
Dozens of people remain missing after the deadliest US tornado in nearly six years, with fears the number of dead will rise.
US weather officials said an “outbreak of tornadoes” were unleashed by a vast storm system crossing a wide area of the southeast on Sunday.
The severe weather destroyed and damaged multiple homes and businesses, snapped trees and left a trail of destruction and weather warnings extending into Georgia, Florida and South Carolina.
Emergency workers rushed to join search and rescue efforts in hard-hit Lee County, Alabama, and spent the night pulling the dead and injured from the wreckage.
At least 23 were confirmed dead in Alabama. Lee County Sheriff Jay Jones said that children were among them.
He said several people had been taken to hospital “some of them with very serious injuries,” while others were reported missing.
Describing the devastation, he added: “It looks like someone almost just took a giant knife and scraped the ground.”
“The challenge is the sheer volume of the debris where all the homes were located,” he told CNN. “It’s the most I’ve seen that I can recall.”
Drones equipped with heat-seeking devices flew overhead to scan the area for survivors but the dangerous conditions halted the search.
Mr Jones said the storm’s path of destruction stretched for miles through Lee County.
In places the path of the tornado was nearly a mile (1.6km) wide.
Authorities had to pause search efforts overnight because conditions were too dangerous in the dark due to large amounts of debris.
“All we could do is just hold on for life and pray,” said Jonathan Clardy, who huddled with his family inside their trailer as gusts ripped off their roof.
He added: “It’s a blessing from God that me and my young’ns are alive.”
Lee County Coroner Bill Harris said he was forced to call in help from the state because there were more bodies than his four-person office could handle.
“I’m not going to be surprised if we don’t come up with some more deceased. Hopefully we won’t,” Mr Harris said.
He said almost entire families were among the dead, including a child as young as six.
Families have lost their homes and belongings, with survivors of the tornado searching through debris to recover what they can.
Julie Morrison managed to find her family’s safe, her husband’s motorcycle boots and her embossed Bible from what is left of her home.
She told reporters she and her husband had sheltered in the bathtub, with her husband jumping in at the last minute before the tornado lifted their house off its foundation and flung it into nearby trees.
“We knew we were flying because it picked the house up,” Mrs Morrison said.
The National Weather Service updated their earlier statement that a tornado with at least an EF3 rating – saying a EF4 tornado had caused the 24 mile (39km) path of destruction. They added a second tornado may also have been active.
It said radar and video evidence showed what looked like a large tornado crossing the area near Beauregard shortly after 2pm.
The agency’s chief meteorologist Chris Darden said the “monster tornado” was the deadliest twister in the US since May 2013 when 24 people were killed in Moore, Oklahoma.
President Donald Trump tweeted late Sunday: “To the great people of Alabama and surrounding areas: Please be careful and safe… To the families and friends of the victims, and to the injured, God bless you all!”
He later said he told the Federal Emergency Management Agency to give Alabama “the A plus treatment”.
Alabama Governor Kay Ivey said the state was working to help families who had been impacted.
“Our hearts go out to those who lost their lives in the storms that hit Lee County today,” Ms Ivey wrote on Twitter.
“Praying for their families & everyone whose homes or businesses were affected.”