In Missouri and Kentucky, the storm system spans the Midwest United States has more than 20 people left.

Kentucky Governor Andy Beshear said 14 of the dead were in his state. At least nine deaths have occurred after the tornado triggered a massive casualty event that authorities called southeast Kentucky.

Authorities said a twin couple also suffered serious injuries when they tore in Laurel County late Friday.

"Search for damage to the damaged area," Sheriff John Root's office said in a statement posted on social media.

Rescuers “are searching for possible survivors all night. That’s what we’re continuing to do,” said Gilbert Acciardo, a spokesman for the sheriff’s office.

Kentucky Governor Andy Beshear said his office will be released immediately after getting more information.

"We know it's a tragic event," he said in a statement.

In Laurel County, a tornado hit shortly before midnight.

"Tonight here has changed life here forever. It's a moment we're together and we pray for this community," London Mayor Randall Weddle, Kentucky, told WKYT-TV. "I've never seen everything I've seen here tonight. There's a lot of destruction."

The storm was part of Friday’s weather system that killed seven people in Missouri and spawned a tornado in Wisconsin, leaving hundreds of thousands of customers in the Great Lakes area without power and brought a heat wave of punishment to Texas.

St. Louis, Missouri Mayor Cara Spencer confirmed five deaths in her city and said more than 5,000 homes were affected.

"It's really real, it's really devastating," she said, adding that the city is declaring an emergency and Friday's night curfew that has caused the most damage nearby.

The number of injured people is not immediately known. Barnes-Jewish Hospital received 20 to 30 patients from the storm, some of whom were severe and expected to be discharged Friday night, hospital spokesman Laura High said.

She said St. Louis Children's Hospital has received 15 patients, two of whom are expected to stay in the hospital until the weekend.

The National Weather Service (NWS) radar says the tornado is between 2.30pm and 2.50pm in Clayton, Missouri, and is located in the St. Louis area of ​​Missouri. The obvious tornado was in the Forest Park area, the location of the St. Louis Zoo and the location of the 1904 World Expo and the Olympic Games of the same year.

At the Centennial Christian Church, William Pollihan, chief of the St. Louis Fire Department, told the Associated Press that three people must be rescued after part of the church collapses. One of them died.

Stacy Clark said his mother-in-law, Patricia Penelton, died in the church. He describes her as a very active church volunteer who plays many roles, including being part of the choir.

Jeffrey Simmons SR, who lives across from the church, heard an alarm on his phone, and the light went out.

"The next thing you know is a lot of noise, a lot of wind," he said, and he and his brother sheltered in the basement. Later, he realized it was worse than he thought, and said, “Everything was torn.”

Falling trees and parking lights also caused traffic stalemate during a Friday afternoon commute, with officials urging people to stay home.

John Randle, a 19-year-old Missouri-St Louis University student, said he and his girlfriend were at the St Louis Art Museum during the storm and were busy with the basement with about 150 other people.

"You can see the doors open, the branches fly, people run," he said. "A lot of people are caught outside."

St. Louis Zoo spokesman Christy Childs said in the text that the zoo will be closed on Saturday due to trees and other damages. Childes said all animals were safe and there were no reports of injuries to staff, guests or animals.

Sheriff Derick Wheetley wrote on social media that a tornado attack in Scott County, about 130 miles (209 kilometers) south of St. Louis, killed two people, injured several others and destroyed multiple homes.