Severe storms hit Mississippi, Alabama and Texas on Friday, producing hail the size of golf balls and prompting the authorities to warn residents they were in a "life-threatening situation".

The National Weather Service issued an alert to people in the path of the tornado and said: "To protect your life, TAKE COVER NOW!

"You are in a life-threatening situation. Flying debris may be deadly to those caught without shelter... Considerable damage to homes, businesses, and vehicles is likely and complete destruction is possible."

The Mississippi Emergency Management Agency said in a Twitter post that search and rescue teams from local and state agencies were deployed to help victims impacted by the tornadoes.

The agency confirmed early on Saturday that 23 people had died, four were missing and dozens were injured.

A few minutes later, the agency tweeted: "Unfortunately, these numbers are expected to change."

The number of fatalities means the storms that ravaged parts of Mississippi overnight were the deadliest in the state in more than a decade.

Read more: Photos show how deadly storm has reduced buildings to rubble

The tornado caused destruction in the rural Mississippi towns of Silver City and Rolling Fork on Friday night before continuing to sweep northeast towards Alabama at 70mph.

Rolling Fork Mayor Eldridge Walker told CNN that his town was essentially wiped out.

Video shot as daylight broke showed houses reduced to piles of rubble, cars flipped on their sides and trees stripped of their branches. Occasionally, in the midst of the wreckage, a home would be spared, seemingly undamaged.

"My city is gone. But we are resilient and we are going to come back strong," Mr Walker said.

People were trapped in piles of rubble and damage had caused gas leaks in Rolling Fork, local newspaper Vicksburg News reported the Sharkey County Sheriff's Office as saying.

President Biden said in a statement: "Jill and I are praying for those who have lost loved ones in the devastating tornadoes in Mississippi and for those whose loved ones are missing.

"The images from across Mississippi are heartbreaking. While we are still assessing the full extent of the damage, we know that many of our fellow Americans are not only grieving for family and friends, they've lost their homes and businesses."

Shelters were opened for those whose homes were damaged by the storms.

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The damage in Rolling Fork was so widespread that several storm chasers - who follow severe weather and often put up livestreams showing dramatic funnel clouds - pleaded for search and rescue help. Others abandoned the chase to drive injured people to the hospitals themselves.

The Sharkey-Issaquena Community Hospital on the west side of Rolling Fork was damaged, WAPT reported.

Some law enforcement units were unaccounted for in Sharkey County where Rolling Fork is based, according to local media.

According to poweroutage.us, 40,000 customers were without power in Tennessee; 15,000 customers were left without power in Mississippi; and 20,000 were without power in Alabama.

The storms in Mississippi were not as deadly as those that left 31 people dead in the state in April 2011.

In Texas, two tornadoes with 100mph winds struck around 5am on Friday, leaving five people injured.

The initial storm was a "supercell", which brews the deadliest tornadoes and most damaging hail, said University of Northern Illinois University meteorology professor Walker Ashley.

Friday's storm was a night time, wet one which is "the worst kind", he said.

Earlier on Friday a car was swept away and two passengers drowned in Missouri during torrential rain that was part of a severe weather system.

By early Saturday, tornado watches remained in parts of eastern Mississippi and in northern Alabama, according to the weather service. Earlier, those watches covered almost all of Mississippi.