MOORE, Okla. - 4:45 p.m. update:
The National Weather Service says the tornado that hit Moore, Okla., was a top-of-the-scale EF-5 twister with winds of at least 200 mph.
Spokeswoman Keli Pirtle said Tuesday the agency upgraded the tornado from an EF-4 on the enhanced Fujita scale to an EF-5 based on what a damage assessment team saw on the ground. The weather service uses the word "incredible" to describe the power of EF-5 storms.
The weather service says the tornado's path was 17 miles long and 1.3 miles wide.
Pirtle says Monday's twister is the first EF-5 tornado of 2013.
9:45 a.m. update:
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.
Rescue crews are working 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.
Officials say the Oklahoma Medical Examiner's Office confirms at least 51 people were killed in Monday's twister, including at least 20 children. Those numbers were expected to climb.
The center of the devastation is in Moore, a community of 41,000 people 10 miles south of Oklahoma City.
More than 120 people were being treated at hospitals, including about 50 children. Amy Elliott, spokeswoman for the Oklahoma Medical Examiner's Office, said Tuesday that there could be as many as 40 more fatalities from Monday's tornado.
People wearing neon-green vests were joined by residents in the search through rubble. Neighborhoods are flattened and homes blown apart.