Severe weather has killed 11 people and injured 23 in the US state of Georgia, emergency officials say.

A state of emergency has been declared in seven counties in south-central Georgia, Governor Nathan Deal said. More storms and a “tornado outbreak” are expected in northern Florida and southern Georgia, the National Weather Service says. Four people were killed by tornadoes in Mississippi on Saturday. The Georgia Emergency Management Agency said the 11 victims were in the southern Cook, Brooks and Berrien counties.

Seven of those killed were at a mobile home park in Cook County apparently struck by a tornado overnight. Cook County coroner Tim Purvis said numerous mobile homes had been “levelled” before dawn on Sunday in the park near the city of Adel. He said emergency teams were still searching for survivors. Mr Purvis estimated that the park has about 40 mobile homes in total, and roughly half were destroyed.

“These storms have devastated communities and homes in South Central Georgia, and the state is making all resources available to the impacted areas,” Governor Deal said in a statement. In Brooks County, coroner Michael Miller said two people died when an apparent tornado tossed a mobile home around 100 yards into the middle of Highway 122.

Swathes of the south-eastern United States have been hit by storms over the weekend. In southern Mississippi, four people died in the path of a tornado with winds above 218 km/h (136 mph). The National Weather Service (NWS) warned a “severe thunderstorm and tornado outbreak” was expected across north Florida and south Georgia, with the “severe threat also expected to extend southward into central Florida and northeastward into South Carolina”.

In a tweet, the NWS in Atlanta/Peachtree City said rainfall had been significant in the past 24 hours, with the city of Charlotte getting 13.6cm (5.3 inches). The Georgia Emergency Management Agency issued advice on the best and worst places to shelter from a tornado late on Saturday, advising locals in the path of a tornado to cover themselves with blankets or a mattress for protection.