Powerful tornadoes have killed at least 35 people in four US states, bringing the death toll to at least 41 from a week of deadly late-winter storms.
The tornadoes splintered homes, damaged a prison and tossed around vehicles across the region, leaving at least 13 people dead in southern Indiana, another 12 in neighbouring Kentucky, two more in Ohio, and one in Alabama, officials said.
The latest line of storms battered a band of states from Ohio and Indiana on southward to Alabama and Georgia.
"We are no match for Mother Nature at her worst," Indiana Governor Mitch Daniels said in a statement, adding that he would visit the stricken southeast corner of the state today.
Another possible storm-related death occurred in Henryville, Indiana, where television images showed homes and a school blown apart.
Televised video taken from the air showed rescue workers in Indiana picking through one splintered house, residents sifting through the ruins of a home, and a school bus thrown into a building.
Several warehouse-like structures had their roofs ripped off.
Major Chuck Adams of the sheriff's office in Indiana's Clark County said there was extensive damage to a school in Henryville but said: "All the children are out. No injuries to any of them, just minor scrapes and abrasions."
An Indiana official confirmed 13 deaths from the tornadoes on Friday, in four southeastern counties. A spokesman for Kentucky's Department of Public Health reported a statewide death toll of 12, while Ohio officials said there were two deaths in a single county.
"There's a possibility we could have additional fatalities," in southwestern Ohio said Kathy Lehr, the director of public information in Clermont County.
The Ohio victims were a 54-year-old man and a 64-year-old woman who was a city council member in the town of Moscow, Ms Lehr said.
Many homes in the county had suffered damage, including some in which buildings were swept off their foundations.
Storm warnings were issued throughout the day from the Midwest to the Southeast, and schools and businesses were closed ahead of the storms after a series of tornadoes earlier in the week killed 13 people in Kansas, Missouri, Illinois and Tennessee.
"We may not be done yet," said John Hart, a meteorologist at the US Weather Service's Storm Prediction Center in Norman, Oklahoma.
As night fell and temperatures cooled, the line of storms appeared to weaken somewhat as they travelled eastward, but the US National Weather Service warned of another possible outbreak of tornadic weather in Saturday's early hours.
Severe thunderstorms and tornadoes were likely over an area stretching from Indiana and Ohio into Kentucky, Tennessee, Mississippi and Alabama.
This week's violent storms raised fears that 2012 will be another bad year for tornadoes after 550 deaths in the United States were blamed on twisters last year, the deadliest year in nearly a century, according to the Weather Service.
The highest death tolls were from an April outbreak in Alabama and Mississippi that claimed 364 lives, and from a May tornado in Joplin, Missouri, that killed 161 people. There were two tornado-related deaths earlier this year in Alabama.