At least 27 people were missing in Shenzhen, Guangdong province, after a landslide hit an industrial park on Sunday morning.

Twenty-two residential and factory buildings were also destroyed in the disaster in Guangming New District.

More than 900 people in the park escaped unharmed, the local government said.

Nearly 1,500 rescue workers were sent to the scene. Four people were saved from collapsed buildings, three of them with minor injuries, the government said.

The landslide happened at 11:40 am, and survivors said it took 20 minutes for the mudslide to sweep down from a hill, giving them time to escape.

President Xi Jinping urged the authorities to spare no effort in the search and rescue work, to minimize casualties.

A worker at PetroChina Co surnamed Yang said he heard two explosions after the landslide happened, which he thought may have occurred in natural gas pipelines.

"I walk along this road every day. There was a lot of earth piled up on the hill," Yang said. He said the earth was dug out from construction sites, which might have caused the landslide.

Hu Zhantao, an engineer at China Railway 16th Bureau Group Co Ltd, who led a rescue team, said mud at the scene was 4 to 5 meters high, and it was difficult for rescue workers to search for survivors as it was still raining.

Cheng Yi Quan, a patient being treated at a hospital in the area, said he and his wife were asleep when the landslide happened.

They ran out of their building immediately after they saw other buildings collapsing.

"We didn't even have time to put on any clothes. We ran for 20 minutes before we reached safety," Cheng said.

Guangming New District, in northwest Shenzhen, is home to the information technology, new material and new-energy industries. As of December last year, 22,000 enterprises were registered there, of which 142 were national-level high-tech firms.

Contact the writers at grace@chinadailyhk.com and sally@chinadailyhk.com