A devastating tornado has obliterated parts of suburban Oklahoma City.

Rescuers have spent the night looking for more victims. Fifty-one people have been confirmed dead so far, but officials say the number could increase to 90.

Witnesses are describing the area as resembling a war zone. Oklahoma’s Lieutenant-Governor,  Todd Lamb, says it looks as if a lawnmower blade four kilometres wide swept through the area.

Twenty children died when an elementary school was flattened by the twister in the town of Moore. Rescuers continue to pick through the rubble, hoping to find more survivors.

US President Barack Obama has declared the region a major disaster area. He will be meeting with his disaster response team this morning before he makes a national address at 10:00 this morning.