At least 25 people have been killed and dozens injured after a tornado and strong thunderstorms ripped across Mississippi, leaving hundreds without shelter, state officials say.

Axar.az reports that Mississippi's emergency management agency said on Saturday afternoon that the death toll had risen to 25, with dozens more injured. Four people who had been reported missing earlier had been located, the agency said.

The tornado stayed on the ground for about an hour and cut a path of destruction some 274km long, according to Nicholas Price, a meteorologist with the National Weather Service in Jackson, Mississippi.

The tornado struck Silver City, a town of 200 people in western Mississippi, as well as Rolling Fork, with a population of 1900, which was hardest hit. Parts of the state remain under tornado warning.