Dozens of people have been killed in violent tornadoes that cut a swathe of destruction across southern states.

The roof was torn from this shop in a mall in Memphis, Tennessee.

At Union University in Jackson, Tennessee, a college dormitory was wrecked.

Students were trapped in the rubble, prompting a major rescue operation.

Doctors were quickly on hand to treat the injured.

The US National Weather Service said dozens of tornadoes had touched down in an area overlapping three states.

The morning after, survivors surveyed the wreckage of their homes and lives.