Rescuers combed through rubble on Saturday after a powerful storm tore across Mississippi overnight, killing at least 25 people there and another in Alabama, levelling dozens of buildings, and spawning at least one devastating tornado.

One of the two tornadoes that terrorized southeastern Mississippi on Sunday has been confirmed as the state's widest tornado on record. The EF4 vortex with winds topping 170 mph was as wide as two miles as it carved a 67-mile path.