Six workers were killed and another three were injured in an accident that occurred at a construction site in Beijing on Monday afternoon, local authorities said.

The accident happened around 2:20 p.m., when the walls of a basement that was under construction collapsed in the city's Chaoyang district, a district government spokesman said.

The injured have been sent to a local hospital for treatment. Their injuries were not life-threatening, the spokesman said.

The managers of the construction company responsible for the site, as well as property administrators, are being questioned by police. The cause of the accident is under investigation.