The National Weather Service issued multiple tornado and severe thunderstorm warnings early Saturday for areas in Alabama, Kentucky, Mississippi, Tennessee, Illinois, Indiana and Texas.

A powerful system of storms is sweeping across the Midwest and South, raising tornado warnings. In Texas, wildfires erupted and high winds caused three fatal crashes, officials said.

The meteorological agency said: "If you live in these areas, get to the sturdiest structure you have access to and remain in place until the storms pass." Mike Kehoe, governor of Missouri - where the 11 deaths were reported across four south-easterly counties - said the state had been "devastated by severe storms and tornadoes,

Hundreds of homes were destroyed as wildfires swept across Oklahoma, prompting authorities to issue evacuation orders.