Emergency workers in the US are continuing to search for survivors of the gigantic tornado that tore through a suburb of Oklahoma City on Monday.
Rescuers worked through the night and into the morning in the rubble in Moore, the worst-hit area.
Entire neighbourhoods were flattened by winds of up to 200mph (320km/h).
At least 24 people were confirmed dead, including nine children, the chief medical examiner said. Earlier, officials said 51 were confirmed dead.
"We have got good news. The number right now is 24," Amy Elliott, chief administrative officer at the Oklahoma Office of the Chief Medical Examiner, told reporters.
"The prior figure of 51 dead may have included some double-reported casualties."
At one point, as many as 91 people were feared dead.
Oklahoma Governor Mary Fallin said it was too early to confirm the number of dead. Some bodies had reportedly been taken directly to funeral homes and were awaiting a final count, she said.
Moore Fire Chief Gary Bird said on Tuesday afternoon that emergency workers were nearing the end of their search. He was "98 percent sure" there were no more survivors or bodies to recover.
"We will be through every damaged piece of property in this city at least three times before we're done, and we hope to be done by dark tonight," he said earlier.
One search and rescue worker at a school that stood directly in the tornado's path told CBS News that officials suspected some of the children who died had been trapped in a pool of water.
"The children were in the main hallway, which is where they were supposed to be during their tornado drills, and the roof collapsed on top of them," Becky Nelson said.
"They suspect waterlines broke and the children drowned because they couldn't get up from the debris."
Albert Ashwood of the Oklahoma Department of Emergency Management said the two schools hit by the tornado, Plaza Towers Elementary and Briarwood Elementary, did not have safe rooms that protect against the high winds of tornados.
More than 100 schools in Oklahoma had been provided with state-funded safe rooms, Mr Ashwood said, but not those two.
President Barack Obama offered his prayers to the people of Moore and pledged whatever assistance they needed during the disaster response.
"The people of Moore should know that their country will remain on the ground, beside them, for as long as it takes," he said.
Betsy Randolph of the Oklahoma Highway Patrol told the BBC there had been flashes of good news during the long night's search for bodies.
"I was hearing just a few moments ago we believe about 101 people were found alive in cellars and different places throughout the city," she said.
"As far as we're concerned, if one person is unaccounted for, we're going to stay and we're going to search until we find that one person."
Heavy-lifting equipment was deployed under bright floodlights as the operation went on through the night and continued as dawn broke.
More than 200 Oklahoma National Guardsmen as well as personnel from other states were called in to help the search-and-rescue effort.
In the background, the weather remained unsettled with regular lightning strikes spotted.
President Obama has declared a major disaster in Oklahoma and ordered federal authorities to join in the search efforts.
The twister hit Moore, a suburb of about 55,000 people, at 15:01 (20:01 GMT) on Monday and remained on the ground for about 45 minutes.
Gov Fallin said the trail of destruction was about 20 miles (32km) long and the tornado was as wide as two miles at times.
"There's just sticks and bricks basically," she said after an aerial tour of the disaster zone.
About 237 people were treated in hospitals, and mental health facilities will be set up in the affected area, Gov Fallin said.
The storm left a tangle of ruined buildings, piles of broken wood, overturned and crushed cars and fires in some places.
Many houses in the area are built on hard ground without basements, so many residents struggled to find shelter.
"We locked the cellar door once we saw it coming, it got louder and next thing you know is you see the latch coming undone," survivor Ricky Stover said.
"We couldn't reach for it and it ripped open the door and just glass and debris started slamming on us and we thought we were dead."
The National Weather Service said Monday's tornado measured EF-4 on the five-point Fujita scale - the second most powerful type.
Tornadoes, hail and high winds also hit Iowa and Kansas, part of a storm system stretching from Texas to Minnesota.
On Sunday, another tornado killed two people near Shawnee, Oklahoma.
The town of Moore was hit by a severe tornado in May 1999, which had the highest winds ever recorded on Earth, over 310mph.
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