XINING -- Twelve people have been confirmed dead and four remain missing as of 6 pm Friday after a steel cable snapped during bridge construction in Northwest China's Qinghai province, according to the emergency command headquarters handling the accident.

The cable broke during a tensioning operation at around 3:10 am Friday at the site of the bridge under construction on the Qinghai section of the Sichuan-Qinghai Railway in Jainca county, Huangnan Tibetan autonomous prefecture. The failure caused a 108-meter steel girder arch rib to collapse, with 16 workers present at the site at the time of the accident.

By 2 pm Friday, rescue efforts involved 806 personnel, supported by 91 vehicles, 27 boats, one helicopter and five robots. Six local hospitals have opened green channels to carry out medical treatment.

Rescue personnel are making all-out efforts to search and rescue the missing, providing medical care and offering support to affected families.

Following the report of the accident, the Ministry of Emergency Management immediately dispatched a working group to the site to guide rescue operations, and urged efforts to verify the situation of the people involved in the accident and mobilize specialized rescue teams to do everything possible to locate and rescue the individuals who have fallen into the water.

The cause of the accident should be identified as soon as possible and efforts should be made to resolutely prevent similar accidents, the ministry said.

The bridge under construction over the Yellow River is a steel truss arch design. Its main span was expected to be closed by the end of this month.