Shenzen city’s deputy mayor, Liu Qingsheng, told a press conference that initial investigations indicated that at least 33 structures had been buried or damaged after Sunday’s landslide, state news agency Xinhua reported.

Among them were 14 factory buildings, 13 low-rise buildings, three dormitories, two office buildings and a canteen.

Authorities had earlier reported that 91 people were missing, but the figure was revised to 85 Monday evening.

The Ministry of Land and Natural Resources said the collapse of a nearly 20-story high “unstable” pile of dirt and construction waste had triggered the landslide.

The Hong Kong-based South China Morning Post reported that the landslide spread across an area of more than 100,000 square meters (119,600 square yards) at the industrial park.

Seven people have been rescued, with none suffering life-threatening injuries.

It also reported residents as saying that they had submitted complaints about the dump pile to authorities – who estimated it as taking up an area of 380,00 square meters – and that there had been a rise in the number of trucks moving waste to the site.

Wang Zhenxin, who formerly worked as a chief engineer at a Shanghai construction firm, told the Post the landslide “is not from a natural mountain, but a huge pile of mud.”

“When one side of the pile is overloaded and the pressure builds up, it pushes the mud on the other side and it spills over,” he added.

President Xi Jinping and Premier Li Keqiang have called for all-out rescue efforts.

While Xi ordered that “everything possible” be done to minimize casualties, Li urged the Ministry of Land and Natural Resources to send officials to help the local government in its rescue efforts.

Xinhua reported experts as saying that another landslide was unlikely.

More than 900 residents had been evacuated from the area as of Sunday evening, with some being accommodated at a makeshift shelter at a sports center.

An investigation into the manmade disaster is ongoing.