(AFP) - At least 23 people have died as violent storms and at least one tornado ripped through the southern US state of Mississippi, tearing off roofs and flattening neighborhoods, officials and residents said Saturday.

The state's emergency management agency said at least four people were missing and dozens were injured, while tens of thousands of people in Mississippi, Alabama and Tennessee were without power.

In the hard-hit town of Rolling Fork, all that was left of an entire row of houses and buildings was scattered debris. Cars were overturned and smashed, fences were ripped up and trees uprooted, according to local television footage.

"At least 23 Mississippians were killed by last night's violent tornados. We know that many more are injured. Search and rescue teams are still active," Governor Tate Reeves said on Twitter.

"The loss will be felt in these towns forever. Please pray for God's hand to be over all who lost family and friends."

Confirming the death toll at 23, the emergency management agency cautioned: "Unfortunately, these numbers are expected to change."

Search and rescue operations were underway in Sharkey and Humphreys counties, about 70 miles (110 kilometers) north of the state capital Jackson.

"My city is gone," Rolling Fork Mayor Eldridge Walker, whose town is located in Sharkey county, told CNN.

"Devastation -- as I look from left to right, that's all I see."

Town resident Shanta Howard said residents had to help remove the dead from the wreckage of their homes.

"That is very disturbing, actually seeing people losing their lives over bad weather like this," she told ABC affiliate WAPT.

- 'Completely gone' -

Woodrow Johnson, a local official in Humphreys County, told CNN his wife woke him up and they heard what sounded like a train. He said his home was destroyed.

"It was a very scary thing," Johnson said, adding his neighbor's house, a trailer, was "completely gone."

The National Weather Service warned residents that as clean-up operations continue, "dangers remain even after the storms move on."

A local tornado watch expired in the early hours of Saturday, meteorologists said. More thunderstorms were expected, but they were not forecast to be severe.

Malary White, a spokeswoman for the Mississippi Emergency Management Agency, said damage assessments would not be possible until officials could do a complete survey in the daylight.

"Our main priority right now, especially for the local first responders, it's life safety and accounting for the people and making sure they are safe," she told CBS News affiliate WJTV.

In Rolling Fork, Walker said several people were rescued from the wreckage of their homes and taken to hospital for treatment.

"A lot of families are hurting. This community is in a situation that we never expected," he told CNN.

"Houses that are torn up can be replaced but we can't replace a life."

© Agence France-Presse