The fires were the latest to break out in the lower Great Plains, where months of drought have combined with unseasonably warm weather to turn the prairies in Oklahoma and Texas into tinderboxes.

Oklahoma County Sheriff John Whetsel said his department had been on the scene of 19 fires on Sunday, but all were now either out or contained so they no longer threatened homes or businesses.

Television reports showed bright orange lines of fire burning in areas on the outskirts of the Oklahoma capital.

Michelann Ooten, spokeswoman for the Oklahoma Department of Emergency Management, said 25,000 acres had burned in the state in the past week, 100 houses had been destroyed or damaged and that one person died last Wednesday.

Since November 1, 250,000 acres had burned in Oklahoma, the State Emergency Operations Centre said.

Temperatures on Sunday reached the 70s (21-25 C) in most of the state, well above normal highs for this time of year. Winds of 35 to 40 mph (56-64 kph) whipped across the plains, the National Weather Service said.

Oklahoma Gov. Brad Henry said he had asked President George W. Bush to expedite the process of declaring the state a disaster area for the purpose of getting federal aid.