The National Weather Service issued a severe weather warning in Illinois, warning of possible cyclones, tornados and fires. Here's the forecast.

The most fatalities were in Missouri. Forecasters warned that tornadoes, hail and violent winds continue to threaten states in the Deep South, from Louisiana to Georgia.

At least 12 fatalities have been reported in Missouri, according to the Missouri State Emergency Management Agency. The deaths come as a massive storm system moving across the country unleashed winds that damaged buildings, whipped up deadly dust storms and fanned more than 100 wildfires.

A sweeping storm system moving across the U.S. threatens to bring tornadoes, blizzards and possibly wildfires to different regions of the country

The threat of violent tornadoes in parts of the U.S. proved deadly as well as destructive as whipping winds moved east into the Mississippi Valley and Deep South on Saturday, with at least six people killed and scores of homes decimated.