A backhoe plunged into a river while demolishing an aging bridge in Thailand.

The heavy machine was tearing down the 40-year-old Bueng Phlan Chai bridge when a section of the structure collapsed in Roi Et province at around 9 am on October 16.

CCTV footage shows the backhoe driving across the bridge before the deck beneath it gave way. The driver, Sutthichai Khurasi, 28, managed to flee before the vehicle was submerged.

Engineers from the Roi Et Municipality Engineering Division arrived at the scene to inspect the damages.

Chanon Likhitbandun, owner of contractor Sahachai Crane Company, said the bridge collapsed likely because of overloading.

He said: 'According to the calculations of the structural engineer, there was no error in the weight bearing when it was just people walking across the bridge. However, when a backhoe weighing several tons was brought in to dismantle it, the vibration from the drilling and the vehicle being overweight may have caused it to collapse.

'From the initial assessment, the damage was at least 500,000 baht, which was fortunately covered by insurance.'

Authorities said the sunken backhoe will be salvaged and repaired.

The demolition will also continue and is expected to finish in around 60 days to make way for a new bridge.