THE death toll from the Oklahoma tornado has risen to 91 with at least 20 children among those killed by the monster 1.6km wide storm.
State medical examiner's office spokeswoman Amy Elliott told local TV station KOCO 5 that 51 of the deaths had been confirmed but that her office was awaiting the arrival of 40 more fatalities.
Authorities say an elementary school in an Oklahoma City suburb took a direct hit from the tornado.
Gary Knight with the Oklahoma City Police Department says there is no word of injuries from the elementary school.
Knight says the school suffered "extensive damage" on Monday afternoon. He did not say which school was hit.
Neighborhoods in Moore, Okla., are flattened and blown apart, with shards of wood and pieces of insulation strewn everywhere.
Television footage also showed first responders picking through rubble and twisted metal in the suburb south of Oklahoma City.
The suburb of Moore was hit hard by a tornado in 1999. The storm had the highest winds ever recorded near the earth's surface.
Earlier, AP reported that children and teachers huddled against winds up to 320 km/h.
At least 145 people were hospitalised in the area, including about 70 children, hospital officials said.
The storm laid waste to scores of buildings in Moore, a community of 41,000 people south of the city.
Block after block lay in ruins. Homes were crushed into piles of broken wood. Cars and trucks were left crumpled on the roadside.
The National Weather Service issued an initial finding that the tornado was an EF-4 on the enhanced Fujita scale, the second most-powerful type of twister.
Rescuers launched a desperate rescue effort at the school, pulling children from heaps of debris and carrying them to a triage centre.
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