Six people were killed and four others injured after a support frame collapsed at a construction site Monday in Langzhong City of southwest China’s Sichuan Province, provincial authorities said Tuesday.

The collapse occurred at a gate between two buildings when workers were pouring concrete.

Local authorities sent excavators, and rescuers and medical staff from neighboring areas including Nanchong City, Cangxi County and Yilong County quickly arrived at the accident site to support rescue efforts.

There were delays in excavating the site as the location of the accident was too narrow for the equipment needed by the rescue team.

As of 12:00 Tuesday, one severely injured worker was sent to the Affiliated Hospital of North Sichuan Medical College in Nanchong City while the other three received treatment at the People’s Hospital of Langzhong City.

The local government has now sent professionals to deal with the aftermath of the accident.