10 killed as powerful tornado slams Oklahoma City

At least 10 people were killed as a powerful two-mile-wide tornado slammed Oklahoma City in South Central US ripping roofs off buildings, levelling homes, and cutting a wide path of destruction.

Besides the 10 dead, at least 20 more, including eight children, were injured. Injuries ranged from minor to critical. More than 32,000 electricity customers in Oklahoma lost power, according to latest reports.

"After the ear-shattering howl of the killer storm subsided, survivors emerged from shelters to see an apocalyptic vision -- the remnants of cars twisted and piled on each other to make what had been a parking lot look like a junk yard," according to a CNN report.

"Bright orange flames roaring from a structure that was blazing even as rain continued to fall," it said.

At least one school was in the tornado's devastation zone in Moore, Oklahoma. There were 75 students and staff at the school when the storm hit, CNN affiliate KFOR reported.

The preliminary rating of damage created by the tornado is at least EF4 (winds 166 to 200 mph) -- the second-most severe classification on a scale of zero to five -- the National Weather Service said.

The tornado was estimated to be at least two miles wide at one point as it moved through Moore, KFOR reported.

Moore Medical Centre in Oklahoma was evacuated after it sustained damage, CNN reported citing a hospital spokesperson.

Even as authorities and rescue workers struggled to get handle on the damage, National Oceanic and Atmospheric Administration's (NOAA) Storm Prediction Centre warned the worst may be yet to come.

"These storms are going to continue producing additional tornadoes. They'll also produce some very, very large hail, perhaps larger than the size of baseballs," NOAA's Bill Bunting told CNN.

The severe weather came after tornadoes and powerful storms ripped through Oklahoma and the Midwest earlier Monday and Sunday damaging or destroying an estimated 300 homes.