MOORE, Okla. — The estimate of the number of people killed by a tornado has been reduced to 24 dead.

Search-and-rescue crews worked through the night after a monstrous tornado barreled through the Oklahoma City suburbs, demolishing an elementary school and reducing homes to piles of splintered wood. At least 24 people were killed, including at least seven children, and those numbers were expected to climb.

As the sun rose over the shattered community of Moore, the state medical examiner’s office cut the estimated death toll by more than half.

Spokeswoman Amy Elliot said she believes some victims were counted twice in the early chaos of the storm. Downed communication lines and problems sharing information with officers exacerbated the problem, she said.

Authorities initially said as many as 51 people were dead, including 20 children.

Teams were continuing to search the rubble in Moore, 10 miles south of Oklahoma City, after the Monday afternoon tornado.

The storm left scores of blocks barren and dark. Rescuers walked through neighborhoods where Monday’s powerful twister flattened home after home, listening for voices calling out from the rubble. A helicopter buzzed above, shining lights on crews below.

By early today, the community of 41,000 people braced for another long, harrowing day.

“As long as we are here ... we are going to hold out hope that we will find survivors,” said Trooper Betsy Randolph, a spokeswoman for the Oklahoma Highway Patrol.

More than 120 people were being treated at hospitals, including about 50 children.