A steel frame collapsed injuring 13 workers at a construction site in Bangkok.

The crew were building a large-scale water infrastructure project when a steel frame gave way at around 7:45 pm on July 6.

The mass of metal bars reportedly struck 13 workers as residents were jolted by the loud crash.

Emergency services arrived after receiving a report, and immediately cordoned off the area to carry out a rescue.

Police Lieutenant Ammarin Ramhring of the Min Buri Police Station, said: 'The incident happened at the Min Buri Water Pumping Station on Soi Nimitmai 6.

'We found 12 workers - nine men and three women - with minor injuries to their arms and legs. There were two Thais, seven Burmese, and three Cambodians. They were given first aid before being taken to Nawamin 9 and Nawamin 1 Hospitals for further treatment.'

The construction supervisor said 160 workers were present at the time of the collapse. None were trapped under the wreckage.

Authorities said the cause of the collapse was being investigated. The Bangkok Metropolitan Administration and engineers were expected to inspect the site.

The 690 billion baht (15.5 billion GBP) construction project, a 70,000-cubic-metre clear water storage tank, is under the Metropolitan Waterworks Authority.

It includes a water intake building, a bridge connecting clear water tanks, and a building to feed chlorine to the reservoirs.

The collapse occurred just a month after a worker was killed at a cursed highway construction in Bangkok.

Burmese migrant worker U Ray, 39, was installing water drainage pipes beneath an elevated expressway when the ground gave way in the early hours of June 8.

He plunged into a 13ft pit filled with rainwater, and was found dead under concrete and mud.

(1 GBP = 44.38 THB)