Tornadoes ripped through an East Texas county on Saturday evening, killing at least four people and injuring dozens of others, and authorities warned the number of casualties could rise.
Three tornadoes were confirmed by the U.S. National Weather Service in Canton, a city about 60 miles (95 kilometers) east of Dallas in Van Zandt County.
The winds flipped over cars, snapped trees, destroyed houses and left roads strewn with debris and fallen power lines, according to photographs and video published by the Dallas Morning News.
"We have at least four fatalities," Canton Mayor Lou Ann Everett said at a news conference on Sunday, adding that number could rise. "The damage was extensive in the affected area. It is heartbreaking and upsetting." Forty nine people had been treated for injuries, she said.
Earlier a Canton fire department captain said he believed five people had been killed.
The mayor urged people to stay away from a sprawling flea market known as First Monday Trade Days, as crews tried to clean up debris.
Texas Governor Greg Abbott deployed a search and rescue team to the area.
The storms caused floods in neighboring states, killing a 72-year-old woman in southwestern Missouri who was washed away in her car, according to local media reports. Another woman was killed when a tree fell on her mobile home in DeWitt, Arkansas, CNN reported.
Downpours that began on Friday were so intense the ground was unable to absorb the rainfall, making flooding likely, said meteorologist Kenneth James of the Weather Prediction Center, part of the National Weather Service.
More than six inches of rain fell in some areas, flooding roads and prompting evacuations, meteorologists said.
The governors of Missouri and Oklahoma declared states of emergency due to flooding.
In the St. Louis area, severe thunderstorms were forecast through Sunday. Some people were told to evacuate and 33 rescues were conducted, mostly in the state's central and southwestern regions, Missouri Governor Eric Greitens said.
Parts of Indiana received up to 8 inches (20 cm) of rain while areas in Oklahoma, Missouri and Arkansas were drenched with up to 4 inches (10 cm), James said.
Heavy rainfall in the Midwest was expected to continue on Sunday, along with wind gusts of 60 miles (95 km) per hour.
Flash floods and strong thunderstorms were forecast for parts of Louisiana, Mississippi and Alabama on Sunday, the National Weather Service said.
(Reporting by Jonathan Allen; Editing by Nick Zieminski and Andrew Hay)