More deadly tornadoes in southern US
Powerful storms are barrelling down on the southern US for a second night, raising the death toll above 20.
Six deaths were reported in Alabama and seven in Mississippi after tornadoes struck on Monday evening, although not all these fatalities were confirmed.
Several tornadoes flattened buildings, overturned vehicles and brought down utility lines on a second consecutive night of devastation.
At least 16 people died in Arkansas, Iowa and Oklahoma on Sunday night.
In Limestone County, Alabama, two deaths were confirmed by the coroner's office and four deaths were reported, although unconfirmed, elsewhere in the county.
In Mississippi, a woman died when driving her car during the storm in Verona, south of Tupelo. Officials said seven people were killed in total across the state but coroners had yet to confirm that number.
The mayor of Tupelo, Jason Shelton, told CNN the damage from the storms was widespread and "devastating". A 21:00 local time curfew was in place on Monday.
Power went out in much of the city as lines went down and trees were torn up by the storm, the US National Weather Service reported.
Giles Ward huddled in a bathroom with his wife and four other relatives as a tornado destroyed his brick house and overturned his son-in-law's four-wheel-drive parked outside his home in Louisville, Winston County, Mississippi.
"For about 30 seconds, it was unbelievable,'' said Mr Ward, a Republican state senator. "It's about as awful as anything we've gone through."
Meanwhile, emergency crews are continuing to search through rubble for survivors of the severe storms which struck one day earlier.
Of the 16 people who died on Sunday night, 14 of them were in the towns surrounding Little Rock, Arkansas. A preliminary death toll there was 16 but it was later amended.
But the number may yet rise as crews search the wreckage of destroyed buildings.
"We're trying to make sure everyone is accounted for," Brandon Morris, spokesman for the Arkansas Department of Emergency Management, told the Associated Press news agency.
Arkansas Governor Mike Beebe said the storm "may be one of the strongest we have seen".
President Barack Obama, on a trip to the Philippines, offered his deepest condolences to those affected on Sunday and said federal emergency officials would be on the ground to help.
"Your country will be there to help you recover and rebuild, as long as it takes," he said.
Mayflower and Vilonia, two small towns in Faulkner County, appear to have borne the brunt of the damage on Sunday.
The Arkansas tornado touched down about 10 miles (16km) west of the city of Little Rock and left a 40-mile (65km) path of destruction.
It is said to have passed through several northern suburbs - including Mayflower where a witness described a twister half a mile wide crossing Interstate 40 on Sunday evening, the National Weather Service said.
Congressman Tim Griffin told Reuters news agency an "entire neighbourhood of 50 homes or so" in Faulkner County had been destroyed, with many "completely gone except the foundation".
Many homes and businesses, including a new secondary school worth $14m (£8.3m), were left in ruins in Vilonia after the storm.
"There's just really nothing there anymore. We're probably going to have to start all over again," said Vilonia schools chief Frank Mitchell after inspecting the wreckage of the school.