Three days of severe storms and tornadoes in the southern United States killed at least 43 people, downed power lines and wrecked hundreds of buildings, officials said.

North Carolina accounted for the bulk of casualties and property losses, with 22 people killed and more than 80 others injured. Significant damage was reported in at least 15 counties and power outages affected more than 200,000 people.

Virginia officials said there were four deaths and unconfirmed reports of three more in the state. Virginia emergency officials said that 177 structures were damaged by the severe weather.

It appeared to be the deadliest US storm since February 2008, when 57 people died in two days from tornadoes in the South and Ohio Valley, said AccuWeather.com meteorologist Andy Mussoline.   

Dominion Virginia Power said the two nuclear reactors at its Surry Power Station in southeastern Virginia shut down automatically on Saturday when an apparent tornado touched down and cut off an electrical feed to the station.   

Backup generators operated normally and both units "are in safe and stable condition," the utility said in a statement.   

Nuclear Regulatory Commission spokesman Roger Hannah said on Sunday no radiation was released during the storm and shutdown. "Everything worked the way it should," he said.

The storms began in Oklahoma on Thursday, then moved through the South and hit the East Coast by Saturday. There were 241 tornadoes reported, with 50 confirmed.

Seven people died as a result of the storms in Alabama, seven died in Arkansas and one died in Mississippi. Two people were killed in Oklahoma when a tornado flattened buildings.

Governors in North Carolina and Virginia declared a state of emergency as authorities scrambled with rescue and cleanup operations.   

In North Carolina, high winds destroyed or damaged more than 460 houses, said Julia Jarema, a spokeswoman for the state's Division of Emergency Management.  

"We're used to hurricanes. We're used to tornadoes. We're used to floods. But we're not used to losing 11 of our citizens," said Bertie County Manager Zee Lamb. The sprawling, rural area in northeastern North Carolina, was the hardest hit.   

"The thing about this storm that is different than a typical tornado was the width," Lamb said. "It wasn't just 100 or 200 yards wide, but a half-mile wide and it stayed on the ground for six miles or so."     

Progress Energy, the main utility in eastern North Carolina, said 220,000 customers were without electricity at the peak of the storm, with 78,000 homes and utilities still without power on Sunday morning. - Reuters