Rescue workers have resumed efforts to free a team of schoolboy footballers and their coach from a flooded cave in Thailand.
Eight boys remain inside the Tham Luang caverns after divers guided four out safely in a high-risk operation late on Sunday, more than two weeks after the group became trapped.
The mission was halted overnight so air tanks placed along the treacherous network of tunnels could be replenished.
The boys freed on Sunday were hungry but in good health, authorities said. They are undergoing medical checks in hospital and because of concerns over infections are not yet allowed close contact with relatives, who were only able to see them through a glass partition.
The rescue operation involved the boys diving through the cave’s narrow, twisting and jagged passageways while tethered to their rescuers.
Authorities said the operation, which involved British divers, had gone “better than expected” and that the healthiest boys had been taken out first.
Thailand’s interior minister, Anupong Paojinda, said the divers involved in Sunday’s rescue would also take part in the next phase as they know best the cave’s conditions.
Chiang Rai governor Narongsak Osatanakorn said efforts resumed at 11am local time (4am GMT) on Monday and that authorities “hope to hear good news in the next few hours”.
Monsoon rains which bore down on a mountainous region of the the far northern province overnight did not raise water levels in the cave, where workers continue to pump water out, he added.
Seven experienced cave divers from the UK involved in the rescue, expected to take up to four days.
“The UK divers are part of the core team, so they will be actively involved and that will include escorting each child out through the flooded passage,” said a British Cave Rescue Council spokesman.
“The operation is being supervised by the Thai authorities. They have had to make a quick decision because they are really concerned about the water level rising.”
Two rescuers accompanied each of the boys freed on Sunday, swimming the the caves “while holding the boys beneath their bodies,” Mr Narongsak. The rescuers are believed to have been forced to detach their oxygen tanks in order to pass through some of the tightest stretches.
The boys have only been learning to dive since 2 July, when they were first discovered perched on a ledge 2.5 miles inside the winding network of caverns.
Cave rescue experts consider an underwater escape to be a last resort, especially with people untrained in diving.
The death of a former Thai navy Seal on Friday underlined the risks. Saman Gunan, who was helping the rescue as a volunteer, and died on a mission to place oxygen canisters along the route.
Mr Narongsak said ahead of Sunday’s successful rescue dive that recent mild weather and falling water levels had created optimal conditions for an underwater evacuation.
However, he warned those conditions would not last if the rain resumes and that rain could shrink the unflooded space where the boys and their coach are sheltering. Heavy downpours began shortly after the four boys were pulled from the cave.
The potential for rising water and the dwindling oxygen levels has added to the urgency of getting the team out, although authorities said efforts to pump water out of the cave had so far been successful in offsetting the rain.
On Sunday night, Thai navy Seals posted a celebratory note on their Facebook page, saying: “Have sweet dreams everyone. Good night. Hooyah.”
The boys, whose team is known as the Wild Boars, became stranded when they were exploring the cave after a practice game on 23 June. Monsoon flooding cut off their escape route and prevented rescuers from finding them for almost 10 days.
The search and rescue operation has involved dozens of international experts, including a US military team.
Elon Musk said his Space X rocket company was testing a “kid-sized submarine” that could be sent to help the trapped boys.
He posted videos on Twitter of the aluminium sub being tested at a swimming pool. If the tests were successful, the sub was to be placed on a 17-hour flight to Thailand.
A spokesman for Musk’s Boring Co tunnelling unit, which has four engineers at the cave, said Thai officials requested the device, which could potentially help the children through narrow, flooded cave passageways.
However, it is unclear if the device is part of any current rescue plans.
Register for free to continue reading
Registration is a free and easy way to support our truly independent journalism
Already have an account? sign in
Join our new commenting forum
Join thought-provoking conversations, follow other Independent readers and see their replies