Rescue teams battled to save a worker trapped under a collapsed subway construction in Bangkok.

Video shows personnel using excavators to widen the 10ft-wide hole where Sarawut, 33, fell on May 19.

The builder reportedly slipped while adjusting a drill in muddy conditions and fell down the 70ft shaft.

Police and firefighters arrived at the scene after receiving a report at 12:30 pm. They found a drilling rig and a backhoe near the excavation shaft where Sarawut had fallen, with the opening covered in wet earth and cement.

Police Major Narin Fuangsri of the Nang Loeng police station said the site was part of the Orange Line Subway extension.

A traffic police officer was first lowered down the hole but he was blocked by dense mud around 30 feet deep inside.

Authorities then dispatched a bulldozer to widen the mouth of the hole while supporting the sides with metal sheets to prevent further collapse.

Phet Pumma, district office director, said rescue efforts were hampered due to the soft and muddy soil which continued to slide into the shaft.

He said: 'The soil is very soft, and we must first stabilise the walls with metal sheets before attempting deeper excavation.'

Cambodian worker Chart, 41, said Sarawut had been working at the construction for around 10 days.

He said: 'We were about to take a break when the ground he was standing on slid. He fell into the hole and was buried under mud. I was so shocked I didn't know what to do. This is the first time I've ever seen something like that happen.'

Officials said Sarawut's body has not yet been found, adding they hope to locate him within 72 hours.