Severe storms that tore through the US states of Missouri, Kentucky and Virginia left more than 25 people dead, leveling homes and businesses while knocking out power for tens of thousands, authorities say.

At least 18 people were killed in Kentucky in the storms Friday night, state governor Andy Beshear posted on X, while officials in Missouri said another seven were dead there.

Two people were also killed by falling trees in Virginia, local media reported.

Jamie Burns, 38, who lives with her husband and son in a trailer home in the town of London, Kentucky, fled to the basement of her sister's brick house while the storm destroyed 100 to 200 houses in the area.

"Things that have been here longer than I have, things that have been here for 30-plus years are just flat," Burns told AFP in a phone interview, her voice quavering.

"It's wild, because you'll look at one area and it's just smashed... totally flattened, like, not there anymore."

Drone footage shared by local media showed scenes of devastation in London, with houses leveled and reduced to splinters and tree trunks standing bare, shorn of branches.

More than 108,000 people were still without power across the three states late Saturday.

Eastern Kentucky, an area historically known for its coal mines, is one of the poorest regions in the country.

"A lot of us live in manufactured homes that aren't safe for tornado weather," said Burns.

In Missouri, five people were killed in the major city of St. Louis, in what authorities said was one of the worst storms in its history, and two in Scott County, the State Highway Patrol said in a statement to AFP.

More severe weather was forecast for Sunday night and Monday.

Asked Saturday by a reporter whether it was the worst storm ever to hit St. Louis, Mayor Cara Spencer replied: "I would describe this as one of the worst storms -- absolutely. The devastation is truly heartbreaking."

She said 38 people in the city were injured and some 5,000 buildings damaged.

In one St. Louis neighborhood, a church was heavily damaged, according to CBS footage, and rescue workers continued to treat victims near the building Saturday morning.

"It's horrific for a tornado to come through here and cause this much damage to the residents and also to the church," Derrick Perkins, a pastor at the Centennial Christian Church, told CBS. "Our hearts are broken."

Bruce Madison, who also works at the church, said the community was coming together in the face of the tragedy.

"Right now, we're just praying for... everybody that they're trying to find right now."

While there were warnings ahead of the severe weather -- Beshear had protectively declared a state of emergency Friday -- the death toll may raise questions about whether sharp cuts by the Trump administration have left National Weather Service forecasting teams dangerously understaffed.

An estimated 500 of the 4,200 NWS employees have been fired or taken early retirement this year, according to the Washington Post.

The United States saw the second-highest number of tornadoes on record last year with nearly 1,800, according to the National Oceanic and Atmospheric Administration (NOAA), trailing only 2004.