At least nine people were killed by the massive tornado that wrecked a small town in Kansas collapsing a hospital and reducing most homes to piles of broken timber, local officials said Saturday.
At least six people were killed in Greensburg, Kansas, after the storm made a direct hit on the small western prairie town late Friday, said City Administrator Steve Hewitt.
Some 30 people were pulled from the rubble of Kiowa County Memorial Hospital in Greensburg as the storm ripped homes off their foundations and even damaged below-ground shelters, according to reports.
Sharon Watson, spokeswoman for Kansas Emergency Management, told CNN a seventh person was killed in an adjacent county. A local newspaper, The Witchita Eagle, later reported two more deaths in Kiowa County where Greensburg is located.
Scores were reported injured and dozens hospitalized.
President George W Bush was briefed on the situation, while the Federal Emergency Management Agency chief, David Paulison, spoke with Kansas Governor Kathleen Sebelius, an administration official said.
"The president's thoughts and prayers are with the people of Greensburg and all those who suffered loss and injury," David Almacy, a White House spokesman, said in a statement.
The US National Weather Center, meanwhile, warned of more severe weather in the central region Saturday, and two new tornadoes were reported in Nebraska to the north.
A tornado warning was issued for a huge swath of land touching seven states from northern Texas to South Dakota, the core of the country's "Tornado Alley."
The National Weather Service warned of "an extremely dangerous and life-threatening situation" for central Nebraska due to the threat of severe tornadoes.
Hewitt said 90 per cent of local homes and buildings were destroyed in Greensburg, about 120 miles (200 kilometers) west of Wichita, and communications in the area were severely disrupted.
"This is a huge catastrophe for this small town. My home's gone, my staff's homes are gone," he said in a press conference.
The town's 1,400 residents were evacuated and ordered not to come back as emergency squads continued to comb the wreckage with tractors and dogs to see if any survivors remained.
"The search and rescue continues. We want to make sure we can find everybody," Hewitt said.
Water, electric and gas utilities were all shut off and a curfew was planned from 8:00 pm to 8:00 am on Sunday.
Television images showed the town virtually levelled, with roofs shredded, branches sheared off trees and school buildings wrecked.
"It sucked the door off of our storm shelter," Greensburg resident Kevin Hillhouse told Wichita television KAKE.
Emergency workers said they were rushing to re-establish communications facilities after the storm wiped out both land line and cellphone services.
The massive wedge-shaped tornado, caught on film by self-styled "storm chasers," struck at about 10:00 pm (0300 GMT Saturday). One of the storm chasers, Darin Brunin, told CNN the storm was "a mile (1.6 kilometer) wide."
People in the town said warning sirens went off about 20 minutes beforehand, giving most a chance to get into storm cellars.
National weather reports put the tornado at between F3 (severe) and F4 (devastating) on a scale of F0 to F5. An F4 storm carries winds of 331-416 kilometers (207-260 miles) per hour.