BEIJING » The number of people missing in a landslide at the site of a hydropower project after days of heavy rain in southern China rose to 41 on Monday with 14 injured, authorities said.

Rocks and mud with a volume of 3.5 million cubic feet buried an office building and the construction workers’ living area at the site in mountainous Taining county in Fujian province early Sunday, according to the county’s Communist Party’s publicity department. An initial count had suggested about 35 people were unaccounted for.

“We were asleep when the mountains began to jolt very strongly and before we knew it, sand and mud were flowing into our room,” survivor Deng Chunwu told the official Xinhua News Agency. It said he and three other workers survived by hiding underneath a supporting pole.

Their room was pushed a distance of 30 feet by the flowing mud, Deng said.

The injured were receiving hospital treatment and in stable condition, Xinhua reported. State broadcaster China Central Television said the injuries included bone fractures.

More than 600 rescuers, including firefighters and police, were searching for the missing and attempting to clear sections of roads leading to the site that had been made unpassable by mudslides and flooding, hindering efforts to get heavy machinery through.

The site under construction is an extension of the Chitan hydropower station, an affiliate of state-owned Huadian Fuxin Energy Ltd., and was expected to begin operations in August 2017, Xinhua reported.

An official at the county department, who gave only his surname, Wei, said by phone that the cause of the landslide was still unclear, but that the area had seen rainfall in the past few days.

Heavy rain has affected much of southern China since Wednesday, triggering floods and landslides.

Xinhua reported that a 75-year-old woman and her 3-year-old great-grandson were washed away in an overflowing river from Friday to Saturday in Hubei province. Rainstorms had earlier led to the evacuation of more than 1,000 people in Guangxi region, and collapsed a road in Guizhou province that left one person dead and one missing.