CHICAGO (AFP) - The death toll from tornadoes that ripped through Oklahoma has risen to nine and includes two children, authorities said on Saturday, less than two weeks after the US state was hit by a monster twister.
The Oklahoma Medical Examiner's Office announced the new fatalities and said five of the victims have not been identified.
The tornadoes hit late Friday and the Oklahoma Department of Emergency Management said that a mother and child were killed as they travelled in their car on an interstate highway.
It was not immediately clear how many people were injured by the series of storms that struck the area around Oklahoma City. The Oklahoman newspaper's website reported that at least 87 people were treated in local hospitals.
As the extent of the devastation became clear on Saturday, cleanup efforts were complicated by severe flooding caused by downpours that drenched the region overnight.
Officials from hard hit Canadian County, speaking on CNN, said crews were working to assess and restore "washed out" places.
Reports said five twisters had struck the area around Oklahoma City, with winds of up to 145km per hour, accompanied by very large hail. Flash floods also hit the area, the Tulsa World newspaper said.
Photos showed streets looking like rivers, with stranded cars submerged in water as high as their door handles in some places.
The National Weather Service's Storm Prediction Centre in Norman, Oklahoma warned that the severe weather was shifting eastward on Saturday, with the Ohio and Mississippi River Valleys set to receive the bulk of the storms.
Friday's storms were far less damaging than the tornado that hit the Oklahoma City suburb of Moore nearly two weeks ago that left 24 dead and demolished large swathes of the town with winds above 322km per hour, affecting a total of 33,000 people.
With an average of 1,200 tornadoes per year, the United States is the most hurricane-prone country in the world. They are particularly prominent in the Great Plains states of Kansas, Oklahoma and Texas, as well as in Florida.