At the same time the rescue teams are working onthe possibility of other entrances to the spot as well.
Photo taken on July 4, 2018 shows friends of the 12 trapped boys singing a song outside of a cave where 12 youth soccer players and their coach are trapped inside, in Mae Sai, Chiang Rai province, in northern Thailand.
The team, which had gone to explore the Tham Luang Nang Non cave in northern Chiang Rai province, got trapped inside after heavy rains flooded its entrance. The downpour flooded parts of the cave and cut off their exit route, forcing the group to forge ahead before finding a raised, dry chamber where they were trapped in total darkness.
He said: 'They may have some belief that their technique is effective for ground water drainage, but anything that is not in the plan must be discussed with us first'.
He added if the high water levels fell, the team would be taken out quickly.
According to a separate doctor's report obtained by CNN, two of the boys and the coach are exhausted and malnourished.
Rescue teams initially didn't plan to rush the boys and their coach out, but heavy rains forecasted for later this week are threatening to push forward those plans.
After the boys were found, Chiang Rai Governor Narongsak Osatanakorn said, "We found them safe".
"All 13 don't have to come out at the same time". Authorities are pumping out water as fast as possible to reach the children while simultaneously conducting diving lessons - wearing masks and breathing, not actual dives - for the group, reported The Associated Press.
In the Israeli system, a string of small devices, similar to handheld radios, pass wireless communications between each other, enabling a link in places regular radios won't work, such as where there are major obstacles blocking the line-of-sight between the two ends of the line. "That's up to the team inside to decide", Kobchai told reporters on Thursday.
'We can't risk having the flood back into the cave'.
Heavy rain is expected to start by Saturday, which will nearly certainly raise water levels in the cave, making passage in some areas more hard if not impossible. The idea is to get some headroom so the boys would not be reliant on scuba apparatus for a long stretch and could keep their heads above water.
Heavy rain is expected to raise water levels inside the cave where the boys are trapped making passage in some parts hard if not impossible.
"They seem to be in good spirits ... so hopefully they can sustain that for an even longer period if they have to."
"This circumstance has clearly shown the power of unity in action, power of love and goodwill towards fellow men regardless of race and religious beliefs", the king said in a letter.
Thai authorities said they are working to install an Internet cable to the cave so that the parents of the boys can talk to their children.
Kian Kamluang, whose 16-year-old son, Pornchai, is in the cave, said she had thought there was a 50 per cent chance that her son would be found. "Who is ready first can go first", he said.
"This requires them do be psychologically able to cope with being underwater. and the dives being not too long or hard", Alan Warild, an expert from the NSW Cave Rescue Squad in Australia, said.
The boys appear relaxed and much more alert than when they were when discovered late Monday by British divers, as they took shelter from surging underground waters on a muddy ledge.
"We are talking kilometers of transport under the water with zero visibility", Claus Rasmusen, a certified Thailand-based cave diving instructor who has been helping with the rescue's logistics, told The AP.
Earlier, Mr Narongsak said the group would be extracted when they were 100% physically fit.