NASHVILLE, Tennessee (Reuters) - A swarm of tornadoes tore through the U.S. midsection on Friday, splintering homes, damaging a prison, overturning trucks and killing at least four people in the hard-hit state of Indiana, officials said.
At least one person died in the southern Indiana town of Henryville, where television images showed homes blown apart and vehicles including a school bus thrown into buildings. Three others died elsewhere in the state.
"The reports coming in are not good," U.S. Senator Dan Coats of Indiana told CNN. "The amount of destruction is pretty significant, and so hopefully there won't be any more confirmed fatalities, but I'm concerned that there might be."
CNN aired aerial images showing rescue workers in Indiana picking through one splintered house, and residents sifting through the ruins of a home. Several large warehouse-like buildings appeared to have their roofs ripped off.
Indiana Homeland Security spokeswoman Emily Norcross confirmed three deaths reported in Jefferson County, while Major Chuck Adams of the Clark County Sheriff's office said one person had died in Henryville but could not confirm the cause.
"We've got extensive damage to the (Henryville high) school there. All the children are out. No injuries to any of them, just minor scrapes and abrasions," Adams said.
The National Weather Service issued storm warnings for throughout the region, urging people to take cover in more than a dozen states. Authorities closed schools, government offices and businesses ahead of the storms.
Earlier in the week, a series of tornadoes killed 13 people in Kansas, Missouri, Illinois and Tennessee.
Seven people were hurt by a suspected twister in northern Alabama, and multiple tornadoes hit in Tennessee and along the Ohio River valley in Illinois, Indiana and Kentucky.
"We're kind of in the middle of a storm," said Kentucky Division of Emergency Management spokeswoman Monica French.
In Kentucky, a small trailer park a fire station and a few homes in Trimble County were destroyed by suspected tornadoes, the Kentucky State Police said. The area is about 40 miles northwest of Louisville.
The fire house and trailer park in Milton "were down to the ground," said the state police's Kevin Woosley, who added there had been some injuries.
To the south in neighboring Tennessee, Nashville Mayor Karl Dean urged businesses to release employees early and non-essential government employees were allowed to leave.
Tractor-trailers were knocked over west of Nashville and power company crews were already out repairing downed power lines from a hailstorm earlier on Friday.
ALABAMA TOWN STRUCK FOR SECOND YEAR
Huntsville, Alabama, which was struck in April 2011 in an outbreak of tornadoes that killed 364 people, was hit again on Friday. An emergency management official said seven people had been transported to hospitals.
"There were two storms that moved across the area, very close together, almost attached to each other," National Weather Service meteorologist Chris Darden said. The Weather service said the area was hit by an EF-2 tornado with winds of 120 miles per hour.
The path of the storm near Huntsville was similar to a devastating tornado on April 27, 2011, part of an outbreak that killed 364 people across Alabama and Mississippi that month.
Authorities said 40 homes were destroyed and 150 damaged in two northern Alabama counties.
A prison, Limestone Correctional Facility, was in the path of Friday's storm, Alabama officials said. High winds caused roof damage to two dormitories, forcing 300 inmates to be moved to elsewhere in the facility.
No one was seriously injured at the prison, which was operating on emergency power, and there was damage to some perimeter fencing, an out building and a canteen.
"There is additional security on the scene and heading to the scene so there is not a public safety issue," said Brian Corbett, a spokesman for the Alabama Department of Corrections.
Forecasters warned that conditions were ripe for another round of tornadoes into Friday evening, leading authorities in Alabama and Tennessee to close schools and put out alerts.
The Weather Service's Storm Prediction Center forecast the "development of a few strong, long-track tornadoes over parts of extreme southern Indiana, central Kentucky and northern middle Tennessee" later on Friday.
Other states likely to see heavy weather were Mississippi, Ohio, Georgia and Illinois, forecasters said.
(Reporting By Bruce Olson, Verna Gates, Tim Ghianni, Peggy Gargis, David Bailey, James Kelleher, Joe Wessels, Susan Guyett, Lee Mueller, Ivonne Rovira; Writing by Andrew Stern; Editing by Cynthia Johnston)