Three workers died and 10 were injured when a building collapsed Wednesday in Chaoyang district. 

Five people were buried under debris after a two-storey auditorium at a steel foundry in Jinzhan village collapsed around 12:48 pm. Rescuers pulled two people out alive, but three died before rescuers could reach them, Chaoyang district government confirmed.

The auditorium, built in 1978, was undergoing maintenance work at the time. 

The rescue took nearly 12 hours, and did not finish until 1:06 am Thursday, according to Beijing Firefighting Bureau, the Legal Mirror reported. 

Ten injured workers were sent to Huaxin Hospital in Chaoyang district. Four are still hospitalized, suffering from head or internal injuries, the report said. 

A media  officer from the Chaoyang Administration of Work Safety said the cause of the collapse is under investigation.

"We've sent staff to the site to investigate, but we don't have a conclusion yet," she said.

The Global Times found that the site was guarded by several security guards who refused the reporter's request to enter. Debris from the collapse could be seen from the gate.

Scores of firemen and 11 fire trucks attended the incident, according to a spokesman from Chaoyang district government.

Several witnesses said they heard an extremely loud noise when the accident occurred.

"The shelves in my shop shook when it happened. I thought it might be an earthquake, but when I went out to see what happened, I was told a building collapsed with several people buried inside," said a shop owner, whose business is only 20 meters from the scene.

Villagers soon started to search and sift through the debris for the missing workers. Firefighters arrived shortly after, witnesses said.

"Many workers who'd been on a break took shovels and other tools to save the buried people," the shop owner said.

Another man, who was working at a nearby building site, claimed at least 20 people were buried by the collapse.

"Over 10 people had climbed out from the ruins when I arrived. Some of them sustained light injuries," he said.