At a news conference at the rescue site on Thursday, Chiang Rai province Governor Narongsak Osotthanakorn, said rescuers and divers were racing against the clock, trying to pump enough water out of the cave so that the boys can make their way out to safety. Although the weather has been relatively dry, water continues to seep into the cave, even as levels have fallen by about 40 centimetres.

"We were racing against time before we found them. Now we're racing against water," Narongsak said.

Thai authorities say the boys do not have to be brought out together, raising a scenario in which a the ones in stronger health could be brought out first, with those feeling weaker staying longer.

On Thursday night, dozens of Thai navy SEALS arrived with oxygen tanks, suggesting either an imminent rescue - or that the boys are low on oxygen. A representative for the navy declined to comment.

The rescuers' main mission is to keep pumping out water, Narongsak added, before heavy rains complicate their efforts. If the boys are not extracted within days, there's a chance that monsoon rains could trap them for months. Experts worry, however, that the boys may be too weak to make the five-hour journey out of the cave, and may panic in their diving gear while making their way through the pitch-black, muddy water and narrow passages.

"Every day we are analysing the weather reported by the meteorological department and seeing how much rain will fall," the governor said.

It will take 11 hours to reach the boys and get them out to dry land, Narongsak said, and communication would have to hold up the entire time to make sure the rescue goes smoothly.

Authorities have tried to extend phone lines into the boys' cave chamber, but the phones fell into the water, preventing any communication so far with the impatient families camped at the rescue site.

The Thai armed forces have made preparations for the boys' eventual return. Helicopters are standing ready at a nearby field to extract those who most urgently need medical attention, and ambulances are parked at the site.

Outside, Pone described the fateful day, which started out like any other with soccer practice. He whipped out his phone to show the last message from his 14-year-old teammate Ekarat Wongsukchan, who is now in the cave.

In the video he sent, the boys are in the same the red and blue T-shirts they were wearing when they were found Monday by two British divers, looking carefree as they ride their bikes around Mae Sai's quiet streets.

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The skies were relatively clear then, he said, but an hour later a downpour began - leading to the flash floods that have trapped the boys deep in the cave system, so far in that it took divers more than five hours to reach them.

"Before that rain, there was nothing. It was just a normal day," he said.

Now the trapped boys are being taught how to dive - quite a feat considering none of them even know how to swim.

"There is zero visibility. It is a confined space," said Matt Fitzgerald, a member of the Australian Federal Police dive team, which has deployed six divers to help with the rescue effort. "It would be terrifying" for them.

Drilling an opening in the cave is also an option, officials say, pointing out that the boys have air so there is probably a shaft somewhere within the system.

American billionaire Elon Musk has offered to help with locating technology from Space X, battery packs from Tesla and drilling from his latest company Boring.

At least 20 Thai army teams have been scouring the mountain range for a possible opening, an army official said, speaking on the condition of anonymity because he was not authorised to speak to the media.

At a church near the boys' soccer field, now occupied by two military helicopters, army officials were studying maps of the region, looking for avenues for drilling.

At the Mae Sai Prasitsart school, daily prayers continue for the trapped boys and their coach. The rescue operation has been accompanied by Buddhist rituals, including blessings from prominent monks. On Wednesday evening, relatives of the boys were presented with framed photos of the Thai king by local authorities, hoping it would lend them resilience.

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Pone is looking forward to the day his friends are free, he said, so he can update them on World Cup results. His phone used to buzz with every goal scored, but now it is flooded with messages of goodwill and support for the team on their group chat app - which the boys in the cave, of course, have not yet been able to read.

"The messages now don't talk about the World Cup, just about how much we miss our friends," he said. "We are trying to support each other, and to remind each other that this will all be resolved."

Washington Post