Teams from the Royal Thai Navy had halted search efforts late on Monday, saying oxygen levels were low in some parts of the complex in the Tham Luang-Khun Nam Nang Noon forest park in the province.
The 12 boys, aged 11 to 16, and their 25-year-old coach, were believed to have been trapped by rising waters inside the cave network when heavy rain hit.
“We must find the children today. We have hope that they are living somewhere in there,” provincial governor Narongsak Osottanakorn told Reuters, adding that each group drafted into the search would work its hardest to find the boys.
The boys’ bicycles and soccer boots were found at the mouth of the Tham Luang caves after they went missing late on Saturday.
A 17-member unit of the Royal Thai Navy has been deployed to find them and underwater drones have joined the search.
So far, the team has searched about 6 km (4 miles) of the 10-km (6-mile)-long cave, said forest park head Damrong Hanpakdeeniyom.
Visitors are usually only permitted to venture about 700 metres (2,300 ft) into the cave complex.
“Inside it is very dark ... and if it rains between July and December then we close it,” Damrong added. “This group went in further than allowed.”
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