The state medical examiner's office has revised the death toll from a tornado in an Oklahoma City suburb to 24 people, including seven children.
Spokeswoman Amy Elliot said Tuesday morning that she believes some victims were counted twice in the early chaos of the storm.
Authorities said initially that as many as 51 people were dead, including 20 children.
Teams are continuing to search the rubble in Moore, 10 miles south of Oklahoma City, after the Monday afternoon tornado.
Oklahoma Gov. Mary Fallin says "hearts are broken" for parents wondering about the fate of their children after a tornado devastated suburban Oklahoma City and officials say the search and rescue effort will continue throughout the night.
Fallin told a Monday news conference that a center for those seeking loved ones has been set up at a church in Moore, where an afternoon tornado flattened entire neighborhoods and destroyed an elementary school with a direct hit. She says responders are working as quickly as they can to sort through the rubble.
The governor says the state will spare no resource in the tornado recovery and will consider using Oklahoma's rainy day fund in the effort.
The White House says President Barack Obama called the governor and told her that he's directed the government and the Federal Emergency Management Agency to provide any assistance she needs.
FEMA has sent a special team to Oklahoma's emergency operations center to help out and dispatch resources.
A mix of volunteers and first responders are combing through debris in an Oklahoma City suburb looking for survivors.
The city of Moore, Okla., was hit by a mile-wide tornado on Monday afternoon.
The National Weather Service says the tornado that hit Moore had wind speeds up to 200 miles per hour, with a preliminary classification of EF-4 on the enhanced Fujita scale.
People wearing neon-green vests were joined by residents in the search through rubble. Neighborhoods are flattened and homes blown apart.
Gary Knight with the Oklahoma City Police Department says an elementary school took a direct hit from the mile-wide tornado, but did not say which school was hit.
Shards of wood and pieces of insulation were strewn everywhere. Television footage also showed first responders picking through rubble and twisted metal.
Television footage shows flattened buildings and fires after a mile-wide tornado moved through the Oklahoma City area.
Homes and buildings in Moore were reduced to rubble, and vehicles littered roadways south and southwest of Oklahoma City.
The suburb of Moore, where Monday's damage was concentrated, was hit hard by a tornado in 1999 that included the highest winds ever recorded near the earth's surface.
Authorities in Oklahoma are spending Monday searching through debris left behind by tornadoes responsible for at least two deaths.
A tornado that started near Norman Sunday afternoon swept the landscape, destroying as many as 35 mobile homes as it moved east toward Shawnee.
Oklahoma's state medical examiner's office spokeswoman Amy Elliot identified the two people who are confirmed to have been killed during Sunday's storms as 79-year-old Glen Irish and 76-year-old Billy Hutchinson. Both men were from Shawnee.
Another storm that first hit Edmond produced a tornado that tracked through the north-central part of the state, hitting the town of Carney, destroying as many as 20 homes.
The National Weather Service says preliminary information from a damage survey team near Shawnee indicates EF4 intensity.
The American Red Cross is setting up three shelters in areas hit by the tornadoes: Shawnee, Little Axe and Carney.
Fallin declared a state of emergency for 21 counties hit by the severe weather.
Thousands of Oklahoma Gas & Electric Customers remain without power, according to OG&E's System Watch.
Information from the Associated Press was used in this report.