Several tornado warnings were in place on Saturday, with Alabama said to be most at risk.
The storms have also brought the threat of ice and snow to parts of the Midwest. Hundreds of flights were cancelled on Saturday at Chicago’s two main airports.
The Bossier Parish Sheriff’s Office in Louisiana said an elderly couple died on Friday, when a tornado destroyed their mobile home, carrying it some 200ft (61m) from its foundations.
Another man in the state was killed on Friday when a tree fell on his home, officials said.
The National Weather Service (NWS) confirmed that three people were killed in Pickens County, Alabama.In Texas, one person died on Friday night when a car flipped into a creek in the city of Dallas. A 44-year-old man in the state’s Nacogdoches County also died when a tree fell onto his home, officials said.