Heavy thunderstorms lashed the southern region of the United States on Tuesday, the National Weather Service said, warning of dangerous tornados in their wake.
"Severe thunderstorms are bringing strong tornadoes, very large hail, and severe wind gusts across parts of the lower to mid Mississippi Valley, Mid-South and parts of the Southeast," it said in a statement.
"Tornado Watches and Warnings are in effect. A few long-track strong tornadoes are possible," it added, citing storms that hit in waves and can last an unusually long time.
Central Mississippi, northeast Louisiana and southwest Arkansas were under a "particularly dangerous tornado" watch, a rare and very serious warning.
The watch was expected to last until 2:00 am Central Times (0800 GMT) Wednesday.
Strong and severe thunderstorms also broke out between eastern Texas and Tennessee, US media reported.
But central Mississippi was expected to bear the brunt of the storms, set to hit in a series of waves.
The Weather Service's Storm Prediction Center declared a rare level four out of five risk for severe storms in the area, media said.