A rare 5.6 earthquake considered to be the stongest on record in the area shook the central US state of Oklahoma late Saturday, reportedly causing significant damage.
After initially putting the magnitude of the temblor at 5.2, the US Geological Survey revised the strength of the seismic event, the second of the day, saying it had reached magnitude 5.6.
The epicenter of the tremor, which occurred at 10:53 pm local time (0353 GMT Sunday), was located just six kilometers (four miles) east of the town of Sparks at a depth of five kilometers.
KJRH television said the Lincoln County Emergency Management agency was reporting significant damage, but offered no details.
The first 4.7-magnitude jolt was reported north of the town of Prague early Saturday.
The readings were based on the open-ended Moment Magnitude scale, now used by US seismologists, which measures the area of the fault that ruptured and the total energy released.
The Oklahoman newspaper said the quake was felt as far as north Texas.
"The picture by the TV fell off the wall and we jumped up because we thought somebody had hit the house," the paper quoted Oklahoma City resident Noeh Morales as saying. "It was like a roaring noise. I've never heard one that bad over here."
Oklahoma City is located 72 kilometers (45 miles) from the epicenter of the quake.