Emergency workers rescued more than 100 survivors from the rubble of homes, schools and a hospital in an Oklahoma town hit by a powerful tornado, and officials lowered the death toll from the storm to 24, including nine children.
The 2km wide tornado tore through Moore outside Oklahoma City on Monday afternoon, trapping victims beneath the rubble, wiping out entire neighbourhoods and tossing vehicles about as if they were toys.
About 237 people were injured and Oklahoma Governor Mary Fallin said the death toll could rise from the deadliest tornado to hit the United States in two years.
"There may have been bodies that may have been taken to local funeral homes," Fallin said.
Seven of the nine children who were killed died at Plaza Towers Elementary School, which took a direct hit, but many more survived unhurt.
"They literally were lifting walls up and kids were coming out," Oklahoma State Police Sergeant Jeremy Lewis said. "They pulled kids out from under cinder blocks without a scratch on them."
The Oklahoma state medical examiner's office said 24 bodies had been recovered from the wreckage, down from the 51 they had reported earlier. The earlier number likely reflected some double-counted deaths, said Amy Elliott, chief administrative officer for the medical examiner.
'A lot of chaos'
"There was a lot of chaos," she said.
Thunderstorms and lightning slowed the rescue effort on Tuesday, but 101 people had been pulled from the debris alive, Oklahoma highway patrol spokesperson Betsy Randolph said.
The National Guard, firefighters from more than a dozen fire departments and rescuers from other states worked all night under bright spotlights trying to find survivors in the town of 55 000 people.
Moore fire chief Gary Bird vowed at a news conference to search through every damaged building "at least three times", as authorities urged people to stay away from the area to allow rescue workers to complete the search.
President Barack Obama declared a major disaster area in Oklahoma, ordering federal aid to supplement state and local efforts in Moore after the deadliest US tornado since 161 people were killed in Joplin, Missouri, two years ago.
"The people of Moore should know that their country will remain on the ground, there for them, beside them, as long as it takes," Obama said at the White House.
Glenn Lewis, the mayor of Moore, said the whole town looked like a debris field and there was a danger of electrocution and fire from downed power lines and broken natural gas lines.
"It looks like we have lost our hospital. I drove by there a while ago and it's pretty much destroyed," Lewis told NBC.
'We are still in shock'
On Tuesday morning, a helicopter was circling overhead and thunder rumbled from a new storm as 35-year-old Moore resident Juan Dills and his family rummaged through the remains of what was once his mother's home. The foundation was laid bare, the roof ripped away and only one wall was still standing. They found a few family photo albums, but little else.
"We are still in shock," he said. "But we will come through. We're from Oklahoma."
National Weather Service Storm Prediction Centre meteorologist Rick Smith said the storm was about 17 miles long with maximum wind speeds of about 190 miles per hour. On the Enhanced Fujita Scale it was ranked EF4, the second most powerful category of tornado.
Authorities warned the town 16 minutes before the tornado touched down just after 3pm, which is more than the average eight to 10 minutes of warning, said Keli Pirtle, a spokesperson for the centre.
The tornado cut a broad trail of destruction through the suburbs south of Oklahoma City, with the worst damage in Moore. The storm system threatened more twisters on Tuesday in several southern Plains states, especially northern and central Texas.
Shelters were opened for families who lost their homes and universities offered to house people.
US representative Tom Cole, who lives in Moore, said the Plaza Towers school, one of five schools hit by the tornado, was the most secure and structurally strong building in the area.
'It was heartbreaking'
"And so people did the right thing, but if you're in front of an F4 or an F5 there is no good thing to do if you're above ground. It's just tragic," he said on MSNBC-TV.
Miguel Macias and his wife, Veronica, had two children at the Plaza Towers school and found eight-year-old Ruby first after rescue workers carried the girl from the destruction. But their son, six-year-old Angel, was nowhere to be found, said Brenda Ramon, pastor of the Faith Latino Church where the family are members.
Ramon and several congregation members spent hours helping the family search for Angel and calling area hospitals. The boy was finally located at a medical centre in Oklahoma City about five hours after the tornado hit.
"It was heartbreaking," Ramon said. "We couldn't find him for hours." The boy had wounds to his face and head, but was not badly hurt, Ramon said. "Their little bodies are so resilient."
Survivors of the storm suffered injuries ranging from minor cuts and bruises to open wounds, impalements and open fractures, said Dr Roxie M Albrecht, the director of trauma and surgical critical care at the Oklahoma University Medical Centre, which cared for 51 children and 35 adults.
Witnesses said Monday's tornado appeared more fierce than the giant twister that was among the dozens that tore up the area on May 3 1999, killing more than 40 people and destroying thousands of homes. That tornado ranked as an EF5 tornado with wind speeds of more than 200mph.
The 1999 tornado ranks as the third-costliest tornado in US history, having caused more than $1-billion in damage at the time, or more than $1.3-billion in today's dollars. Only the devastating Joplin and Tuscaloosa tornadoes in 2011 were more costly.
Monday's tornado in Moore ranks among the most severe in the United States.
Diana Tinnin (60) was at home with her brother when the storm hit. Her three-bedroom ranch-style home had no basement, so they huddled in a bathtub. "I lost my house. Everything fell on top of us." – Reuters