Two more workers were found dead in a collapsed tunnel following an intense five-day search and rescue mission in Thailand.

Ekarat Sri-arayanpong, head of the State Railway of Thailand governor's office, said the bodies of two Chinese men were retrieved from the railway project in Nakhon Ratchasima province in the early hours of August 30.

They were named by officials as Chinese foreman, Hu Xiang Min, and a Chinese backhoe operator, Dong Xin Lin. The third man, a Burmese truck driver, had earlier been recovered.

The Chinese workers' bodies were taken to the Maharat Nakhon Ratchasima Hospital for post-mortem exams. An earlier investigation found that the Myanmar national, whose remains were unearthed earlier on August 29, had died of suffocation.

The tunnel, set to link Thailand to China, caved in and trapped three workers despite no rain falling on August 24 evening.

Rescue teams, including an engineering team sent from China, were racing to save the trio. They had deployed excavators, sniffer dogs, and installed a rescue tunnel, but the individuals could not be saved.

Thailand's Deputy Transport Minister Surapong Piyachote claimed that recent rains may have caused the earth above the tunnel to become heavy.

The two-part rail project reportedly cost more than 520 billion baht (11.7 billion GBP). The first segment was set to be completed by 2028, and the second part by 2029.

(1 THB = 0.022 GBP)