Donald Trump has declared a major disaster exists in Alabama after a tornado swept through the state and killed at least 23 people.

The US president approved a federal disaster declaration and ordered aid to assist state and local recovery efforts.

Mr Trump said he will visit Alabama on Friday to see the damage.

“It’s been a tragic situation, but a lot of good work is being done,” he said at the White House.

It comes after 23 people killed in the deadliest US tornado in nearly six years came into focus on Tuesday with the release of their names by the coroner.

The youngest victim was six and the oldest was 93, while one family lost seven members.

“Just keep those families in your prayers,” Lee County coroner Bill Harris said, two days after the disaster. “It’s a tragic situation.”

The search for victims in and around the devastated rural community of Beauregard continued, with crews using heavy equipment to lift large chunks of wreckage. A man searches through the debris that was his home near Beauregard (Mickey Welsh/The Montgomery Advertiser via AP)

Sheriff Jay Jones said the list of missing people had shrunk from dozens to just seven or eight.

“We’ve got piles of rubble that we are searching just to make sure,” said Opelika fire chief Byron Prather Jr.

“We don’t think we’ll find nobody there, but we don’t want to leave any stone unturned.”

Four children were killed, aged six, eight, nine and 10.

The youngest, AJ, had taken shelter in a closet with his father and older brother when the tornado hit, said Jack Crisp, the boy’s uncle.

“He had them squeezed tight, and he said when it came through, it just took them,” Mr Crisp said.

“It just demolished the house and took them.”

The boy’s father and brother both survived.

Jackie Jones said she and her siblings rushed to her parents’ house after the storm passed and nobody answered the phone. “They usually answer on the first ring,” she said.

The siblings found the home reduced to its foundation.

One of their two brothers who lived at the house survived and was taken to a hospital. But Jimmy Lee and Mary Louise Jones, married for more than 60 years, had died along with their 53-year-old son Emmanuel.

The body of David Wayne Dean, 53, was found by his son in a neighbour’s yard after the twister demolished his mobile home.

He was known as “Roaddog” because of his love for Harley-Davidson motorcycles.

Widow Carol Dean, who was at work when the storm hit, said: “My life is gone. He was the reason I lived, the reason that I got up.” Carol Dean with Megan Anderson and her 18-month-old daughter Madilyn (David Goldman/AP)

The tornado packed winds estimated at 170mph and carved a path of destruction almost a mile wide in Alabama, the National Weather Service said. It travelled a remarkable 70 miles or so through Alabama and Georgia, where it caused more damage.

It was the deadliest tornado to hit the US since May 2013, when a twister killed 24 people in Moore, Oklahoma.

Government teams surveying storm damage confirmed that at least 20 tornadoes struck on Sunday in Alabama, Florida, Georgia and South Carolina.

Cindy Sanford said one of her neighbours in Beauregard died in the storm, and another neighbour remained missing on Tuesday.

“I pray to God that they find her,” Ms Sanford said as picked through remains of her home.

- Press Association