Powerful tornadoes tore through parts of the Deep South on Friday night, killing at least 23 people in Mississippi, obliterating dozens of buildings and leaving an especially devastating mark on a rural town whose mayor declared, “My city is gone.”

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 Saturday that 23 people had died, four were missing and dozens were injured.

A few minutes later, the agency warned the casualty toll could go higher, tweeting: “Unfortunately, these numbers are expected to change.”

Mississippi Gov. Tate Reeves tweeted Saturday that he was on his way to Sharkey County, whose county seat of Rolling Folk was flattened. “Devastating damage — as everyone knows. This is a tragedy.”

The National Weather Service confirmed a tornado caused damage about 60 miles (96 kilometers) northeast of Jackson, Mississippi. The rural towns of Silver City and Rolling Fork reported destruction as the tornado swept northeast at 70 mph (113 kph) without weakening, racing towards Alabama through towns, including Winona and Amory, into the night.

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,” he said.

The National Weather Service issued an alert Friday night as the storm was hitting that didn’t mince words: “To protect your life, TAKE COVER NOW!”

“You are in a life-threatening situation,” it warned. “Flying debris may be deadly to those caught without shelter. Mobile homes will be destroyed. Considerable damage to homes, businesses, and vehicles is likely and complete destruction is possible.”

Cornel Knight told The Associated Press that he, his wife and their 3-year-old daughter were at a relative’s home in Rolling Fork when the tornado struck. He said the sky was dark but “you could see the direction from every transformer that blew.”

He said it was “eerily quiet” as that happened. Knight said he watched from a doorway until the tornado was, he estimated, less than a mile away. Then he told everyone in the house to take cover in a hallway. He said the tornado struck another relative’s home across a wide corn field from where he was. A wall in that home collapsed and trapped several people inside. As Knight spoke to AP by phone, he said he could see lights from emergency vehicles at the partially collapsed home.

The tornado looked so powerful on radar as it neared the town of Amory, about 25 miles (40 kilometers) southeast of Tupelo, that one Mississippi meteorologist paused to say a prayer after new radar information came in.

“Oh man,” WTVA’s Matt Laubhan said on the live broadcast. “Dear Jesus, please help them. Amen.”

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.

The Sharkey County Sheriff’s Office in Rolling Fork reported gas leaks and people trapped in piles of rubble, according to the Vicksburg News. Some law enforcement units were unaccounted for in Sharkey, according to the the newspaper.

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.

Rolling Fork and the surrounding area has wide expanses of cotton, corn and soybean fields and catfish farming ponds. More than a half-dozen shelters were opened in the state by emergency officials.

Mississippi Gov. Tate Reeves said in a Twitter post Friday night that search and rescue teams were active and that officials were sending in more ambulances and emergency assets.

“Many in the MS Delta need your prayer and God’s protection tonight,” the post said. “Watch weather reports and stay cautious through the night, Mississippi!”

This was a supercell, the nasty type of storm that brews the deadliest tornado and most damaging hail in the United States, said University of Northern Illinois University meteorology professor Walker Ashley. What’s more, this was a nighttime one which is “the worst kind,” he said.

Meteorologists saw a big tornado risk coming for the general region, not the specific area, as much as a week in advance, said Ashley, who was discussing it with his colleagues as early as March 17. The National Weather Service’s Storm Prediction Center put out a long-range alert for the area on March 19, he said.

Tornado experts like Ashley have been warning about increased risk exposure in the region because of people building more.

“You mix a particularly socioeconomically vulnerable landscape with a fast-moving, long-track nocturnal tornado, and, disaster will happen,” Ashley said in an email.

Earlier Friday, torrential rainfall in Missouri caused flooding that was blamed for the deaths of two people who were in a car that was swept away by high water. Another person was missing in another Missouri county hit by flash floods.