US storms: At least 11 dead in trail of destruction

The remains of the Beverly Chapel CME Church after a tornado struck Holly Springs, Mississippi

At least 11 people have been killed and scores more injured by a devastating storm which left a path of destruction across the US South on Christmas Eve.

Seven people were killed as tornadoes moved through northern Mississippi overnight, officials said, and three more died in Tennessee and one in Arkansas.

There have been reports of at least 20 tornadoes of varying severity.

A seven-year-old boy was among those killed.

Authorities in parts of Mississippi are conducting a house-by-house search-and-rescue operation after the state was hit by multiple tornadoes.

The boy was inside a car, which was picked up and tossed in the storm. His relatives, who were also in the vehicle, were taken to a hospital for treatment.

Diana Davis looks for family photos in the rubble of her father-in-law's home in Lutts, Tennessee (Photo by Larry McCormack/The Tennessean)

The post office in Lutts was also destroyed by a tornado (photo by Larry McCormack/The Tennessean)

Planes at a small airport in the north-west of the state were overturned and an unknown number of people were injured.

"I'm looking at some horrific damage right now," Clarksdale Mayor Bill Luckett was quoted by the AP news agency as saying.

"Sheet metal is wrapped around trees; there are overturned airplanes; a building is just destroyed."

Mississippi's Interstate 55 was closed in both directions as the tornado approached, the state's Highway Patrol said.

The storms were deadliest in Mississippi

There are reports that one large tornado touched land in Mississippi and travelled 100 miles to Tennessee.

The threat of tornadoes eased as the line of storms moved east on Thursday, but heavy rain and thunderstorms caused flooding and travel chaos in Georgia, Alabama and the Carolinas.

The national Storm Prediction Center in Oklahoma had released a "particularly dangerous situation" warning for the first time since June 2014 when two massive tornadoes destroyed a rural Nebraska town, killing two people.

The possibility of bad weather just before Christmas in the US is not unusual, officials at the centre say.

One year ago a tornado hit south-eastern Mississippi, killing five people and injuring dozens more.

A storm on Christmas Day in 2012 which included several tornadoes damaged homes from Texas to Alabama.