Homeowners after a tornado hit the town of Canton
Homeowners after a tornado hit the town of CantonBrandon Wade/ Reuters

At least 13 people were killed and dozens more injured after a tornado hit several regions in the southern US.

At least four separate tornadoes touched down in eastern Texas on Saturday afternoon, the National Weather Service said.

Flood warnings were issued from eastern Oklahoma to western Kentucky, and included parts of Illinois.

Texas Governor Greg Abbott during a local news conference said, "You saw homes and other buildings that were incompletely flattened, as well as others that were nothing more than rubble."

He also said he "large swath after large swath of devastation."

Canton, Texas, Mayor Lou Ann Everett said on Sunday, "The damage was extensive in the affected area. It is heartbreaking and upsetting." She added that at least 49 people had been injured.

"We won't know exactly what we are dealing with until the sun comes up," she told NBC News. "We have no power. We have three major transmission stations that are damaged."

Arkansas authorities are searching for a 4-year-old boy and an 18-month-old girl who were swept away from their mother. And hail the size of baseballs damaged power lines when it fell in Cameron, Oklahoma, and leaving 12,000 without power.

Some people were told to evacuate the St. Louis area, and 33 rescues were conducted, Missouri Governor Eric Greitens reported.

Rescue forces are still working to locate victims, and the toll is expected to climb.