Oklahoma tornado was strongest category: Official

WASHINGTON (AFP) - The massive tornado that cut a wide and deadly swath through a suburban Oklahoma City town was a top category EF5 system with winds over 321kmh, a weather official told AFP Tuesday.

"It's an EF5," the most powerful tornado classification, said Ms Kelly Pirtle of the NOAA national Severe Storms Laboratory in Norman, Oklahoma, of the wedge tornado that struck Moore, Oklahoma on Monday.

"We have looked at the damage, and estimated windspeeds, and they've determined that the damage is EF5," she added by phone from Norman.

That means the system, which blew homes off their foundations and sent debis flying almost 160km away, had "maximum winds over 200 miles per hour," Pirtle explained.

Rescue teams were still combing through a blasted moonscape that had been Moore after the monstrous tornado struck south of Oklahoma City, killing at least 24 people.

Passengers flying into Oklahoma City could see the track left nature's fury as it played out Monday: the spot where the tornado touched down then chewed through the suburb of Moore like a lawnmower for 45 terrifying minutes.

Nine children were among the dead and entire neighbourhoods were obliterated.