MOORE, Okla. (AP) - The National Weather Service says the tornado that hit Moore, Okla., had wind speeds up to 200 mph.
The weather service's preliminary classification of Monday afternoon's tornado was an EF-4 on the enhanced Fujita scale.
Authorities say emergency crews are working to rescue people trapped in Moore, which is southwest of Oklahoma City.
Oklahoma City Police Capt. Dexter Nelson said emergency crews are trying to reach the affected areas.
A mix of volunteers and first responders are combing through debris in an Oklahoma City suburb looking for survivors..
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.
KWTV reports fatalities; among them a three month old baby and a four year old child..
Shards of wood and pieces of insulation were strewn everywhere. Television footage also showed first responders picking through rubble and twisted metal.
Several children have been pulled out of the rubble alive at a school in an Oklahoma City suburb.
An Associated Press photographer saw several children being pulled out of what was left of the Plaza Towers Elementary School in Moore, Okla., on Monday after a massive tornado hit the region.
Rescue workers lifted children from the rubble before they were passed down a human chain and taken to a triage center set up in the school's parking lot.
The school is southwest of Oklahoma City. Its roof appears mangled and the walls had fallen in or had collapsed.