Officials searching for victims amid the wreckage of Riegelwood cautioned that death toll still could rise.
Authorities say two of the dead are children, reports CBS News correspondent Jim Acosta. Of the 19 people injured in the hospital, four are children too, all in critical condition.
Dozens of homes were destroyed when the tornado struck the Cape Fear River community, about 20 miles west of the coastal city of Wilmington. Searches had found seven bodies in the wreckage by midday, and "that number very well may go up," said Columbus County Commissioner Chairman Kip Godwin, the designated spokesman for the county's emergency management office.
"When a tornado hits a mobile home, it's probably much more devastating," Godwin said. "Most of these homes were blown off their foundations and are now just piles of debris."
Two other people died in North Carolina car crashes amid in the storms' strong wind and pounding rain early Thursday. Another person died Wednesday when a tornado struck his home in Louisiana as the storms began their path of destruction across the South.
"It's pretty well devastated. I've heard about being in a war zone, but this is something to behold," Columbus County Commissioner Sammie Jacobs told CBS affiliate WRAL-TV in Raleigh during a telephone interview.
In Riegelwood, the hardest-hit community, rescue workers used backhoes and front-end loaders to search the rubble of the mobile home park.
Alton Edwards, a member of the volunteer Acme-Delco-Riegelwood Fire and Rescue team, said storm struck "with very little warning."
Also, a tornado watch was issued for eight counties in the eastern part of South Carolina.
Several states have been battered by storms that began Wednesday, unleashing tornadoes and straight-line winds that overturned mobile homes and tractor-trailers, uprooted trees and knocked down power lines.
A tornado cut a path about two miles wide and three or four miles long in Greensburg, La., north of New Orleans, toppling trees and damaging buildings and power lines, said Maj. Michael Martin of the St. Helena Parish Sheriff's Office. A 43-year-old man was killed when the trailer he was in was destroyed, he said.
"That home just exploded," said Gordon Burgess, president of neighboring Tangipahoa Parish.
In Montgomery, Ala., high winds destroyed a skating rink Wednesday, not long after 31 preschoolers and four adults fled to safety. The day care side of the building was the only part that was not flattened, reports CBS News correspondent Mark Strassmann.
One child suffered a broken bone and another sustained a cut to the head, but everyone else emerged unharmed from the crumpled wreck of the Fun Zone Skate Center, which doubled as a day-care facility.
Jon Slaughter, who owns two nearby businesses, arrived at the skating center with two employees about five minutes after the building was ripped apart.
"What I saw was just utter destruction," said Slaughter. "The children were scared, they were cold and dirty. They were crying and upset, but really they were calmer than I thought they would be."
The manager of the day-care center operating inside the building had made everyone get into the section of the building that survived the high winds.
"She may have saved many of these children's lives," the Montgomery Mayor Bobby Bright said.
In Mississippi's Lamar County, emergency operations center director James Smith said a possible tornado struck a subdivision outside Sumrall around 2:50 a.m., damaging or destroying 11 homes.
Smith said six people were taken to hospitals from the Sumrall area, and the Mississippi Emergency Management Agency said two other people were injured in Greene County.
In North Carolina, fallen trees blocked roads in Lincoln County, and another possible tornado struck about midnight in eastern Gaston County, where a steeple was destroyed and part of the roof ripped off a church. Duke Energy reported nearly 3,000 customers without power in Gaston County, about 1,200 outages in Iredell County, and nearly 900 outages in Lincoln County.