At least 91 people are missing after a landslide in southern China buried 33 buildings at an industrial park Sunday. Seven people were reportedly pulled from the rubble as hundreds of rescue workers continued to look for survivors in Guangdong province’s Shenzhen city Monday.

Officials said that 59 men and 32 women were missing and that "signs of life" had been detected at three separate locations, BBC reported, citing state media. About 900 people were evacuated Sunday after the landslide blanketed a 380,000 sq. meter area, according to local reports. China's Xinhua News Agency reported that the landslide caused an explosion at a natural gas pipeline. Workers have reportedly cleaned the area of the damaged pipeline and are repairing it.

The Chinese ministry of land resources reportedly said that the incident took place because of a mountain of waste construction mud in the vicinity. Authorities from the Guangdong province sent a team to investigate and said the accumulation of a large amount of waste meant that mud was stacked too steep, "causing instability and collapse, resulting in the collapse of buildings,” the ministry reportedly said, in a statement.

Chinese President Xi Jinping ordered provincial authorities to put all efforts to minimize casualties, treat the injured and comfort family members, Xinhua reported. Premier Li Keqiang ordered central government officials to help provincial authorities in the search efforts that were being carried out by more than 2,000 rescuers.