YUEYANG, Hunan - Authorities in a rain-drenched central China province said on Sunday that a landslide that killed 12 people and left seven others missing earlier this week was not triggered by man-made causes.

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The landslide hit the village of Guanshan at Friday dawn after torrential rains, estimated to be the heaviest to hit the area in 300 years, pounded the city of Linxiang in Hunan province for about six hours, according to the results of an official probe.

The results said that the region's recent severe drought made the ground more dry than usual, allowing the heavy rains to sweep away sand and rocks. This resulted in a landslide that roared down a mountain slope 300 meters above Guanshan.

The probe, conducted by a panel of experts in the wake of the disaster, found that there were no illegal mines or breached reservoirs in the area where the landslide occurred, effectively ruling out any man-made causes.

More than 50 people were killed and 40 others remain missing after heavy rains inundated four provinces in central and south China this week.

Floods and landslides toppled homes and inundated farms in Hubei, Hunan, Jiangxi and Guizhou provinces, which were dealing with a lingering severe drought just days before the rains fell.