Emergency workers receive no response from boy two days after he fell into a 35-metre support pillar at a construction site.

Thai Ly Hao Nam was heard crying for help shortly after he fell into the pile on Saturday morning, but rescuers received no response from him on Monday as they lowered a camera down to try to locate his position in the 35-metre-long (115-foot-long) support pillar.

The accident occurred at a bridge construction site in the Mekong Delta when the boy was searching with friends for scrap iron.

“I cannot understand how he fell into the hollow concrete pile, which has a diameter of a [25cm, 10-inch] span only and was driven 35 metres into the ground,” Le Hoang Bao, director of Dong Thap province’s Department of Transport, told Tuoi Tre News, a local newspaper.

Efforts to lift the pile with cranes and excavators have so far failed, and rescuers were unable to determine the boy’s position, media reported.

“We are trying our best. We cannot tell the boy’s condition yet,” a rescuer told the AFP news agency by phone, identifying himself only as Sau.

Rescuers have pumped oxygen into the support post and have softened the soil around it, but the pile has tilted slightly, complicating extraction efforts.

On Monday, Prime Minister Pham Minh Chinh asked federal rescue workers to join local authorities to save the boy.