THE 12 Thai boys trapped deep inside a partially flooded cave are not yet ready to dive out, the rescue operation commander said, although forecast heavy rains could speed up their extraction attempt.

Governor Narongsak Osottanakorn, a former governor of the northern Chiang Rai province who is leading the rescue effort, said there were no plans to pull the boys and their coach out overnight but if monsoon rains fell and water rose in the Tham Luang cave over the coming days they could change their plans.

“The boys are not suitable …(they) cannot dive at this time,” governor Osottanakorn told reporters. “Now the problem is the children’s readiness to dive.

“We (will) try to set the best plan. If the risk is minimal, we will try. We are afraid of the weather and the oxygen in the cave. We have to try to set the plan and find which plan is the best.”

Thailand’s Navy SEAL commander earlier said rescuers may have “limited time” to attempt the tricky job of getting the group out — the first official admission waiting out the monsoon period in the cave may not be possible.

The grim reality facing the boys and their football coach has never been more evident. New footage of the daunting conditions facing the group trapped in the flooded cave has been captured by British television network ITV.

Several rescuers can be seen struggling through dark, narrow passages. They can see where they are going only through headlights, and are moving through the flooded cave system holding a rope above them.

It shows the enormous task ahead for the boys, several of who are weak from not eating proper food for days.

With oxygen levels dropping quickly, the rescue mission seen being rehearsed in the new footage could begin at any moment.

ITV: Footage shows the tough conditions in the Thai cave rescue ITV: Footage shows the tough conditions in the Thai cave rescue

The dwindling air supply and race against oncoming monsoonal rain have given the rescue mission fresh urgency.

The risky operation, which claimed its first fatality early Friday morning when a former Navy SEAL died from lack of oxygen, could reach its climax tonight or tomorrow as time runs out.

Explaining the difficulties of the operation on Sky News, Ivan Karadzic, a Danish cave diver volunteering in the risky mission indicated retrieval of the boys could begin at any time.

When asked how soon would it happen, Mr Karadzic responded, “today or tomorrow, I think”.

“There’s few people who have experience rescuing kids from deep inside the cave,” Mr Karadzic said.

Rescuers this afternoon conceded their rescue window was narrowing. In the first official admission the boys cannot wait out the monsoon season underground until October, authorities have warned the window of opportunity to free them is “limited”.

There is now a “limited amount of time” left and little choice but to attempt the tricky extraction and get the boys out, Thailand’s Navy SEAL commander Arpakorn Yookongkaew said.

The level of oxygen in the cave where the boys are trapped has dropped to 15 per cent. The usual level is around 21 per cent.

“We can no longer wait for all conditions (to be ready) because the circumstance is pressuring us,” Mr Yookongkaew said.

“At first we thought that we could sustain the kids’ lives for a long time where they are now, but now, many things have changed. We have a limited amount of time.”

NEW METHOD FLOATED AS TIME RUNS OUT

As the window for safe rescue narrows, engineers are reportedly considering drilling into the cave rather than having the boys swim out with Navy SEAL divers.

Drilling was ruled out as an option early on, but Thanes Weerasin, the president of the Engineering Institute of Thailand, has revealed that a drilling crew are looking at a tunnel with a large hole about 100 metres into it, The Guardian has reported.

“It’s a big hole, about 1.2m by 1m,” Mr Weerasin said.

“You can go down using a rope … I think this place can lead to the children because after your foot touches the ground below, you can walk through using the compass and direct it to the tunnel [where the children are stuck].”

Australian drilling expert Kelvin Brown, who was part of the 2010 rescue of 33 Chilean miners trapped 700m below ground, told the ABC drilling could be useful, but it would come with risks.

“We knew what the formation was, we knew if there were faulted zones, the presence of aquafer,” Mr Brown said.

“I’m not too sure all that information is actually at hand in this Thai scenario. But it’s all possible, as was proven.

“It makes a bit more sense to me anyway, at least for the sake of safe access, to use a drill hole.”

RESCUE MISSION TURNS DEADLY

The new strategy has been suggested after the boys started learning to swim and training with diving experts to use scuba gear from the section of the cave complex where they have been trapped almost two weeks.

A former Thai Navy SEAL who had volunteered in the rescue mission died during the rescue mission while making his way out of the cave complex where the group is trapped.

The man has been identified as retired Navy Petty Officer 1st Class Saman Kunan who volunteered for the operation after having left his post.

Mr Kunan lost consciousness after placing oxygen tanks in the cave and could not be revived despite first-aid attempts by his dive partner.

The cave system in Mae Sai, northern Thailand, is losing oxygen as they continue to try and deliver air supplies to the kids and coach through a pipe. Authorities say the ventilation pipe must reach them today.

A sombre mood has clouded the elation from earlier in the week when the boys were found dishevelled and hungry but alive on a ledge kilometres inside the cave.

Chiang Rai deputy governor Passakorn Boonyaluck told reporters: “It was sad news, a former SEAL who volunteered to help died last night about 2am.

“His job was to deliver oxygen (in the cave). He did not have enough on his way back.”

SEAL commander Mr Yookongkaew said Mr Kunan, who was working in a volunteer capacity, was coming back from the spot inside the Thuam Luang cave where the group had been located when his supplies ran short.

“On his way back he lost consciousness,” Mr Yookongkaew said, adding that a friend had tried to help bring him out.

“But even though we have lost one man, we still have faith to carry out our work.”

RESCUERS TO TAKE ‘MORE PRECAUTIONS’

His death raises doubts over the safety of attempting to bring the group out the same way, through cramped passageways deep inside the waterlogged cave.

Many of the boys, aged between 11 to 16, are unable to swim and none has diving experience.

Asked how the boys could make it out safely if an experienced diver could not, Mr Yookongkaew said the rescue team would take more precautions with children.

“We lost one man, but we still have faith to carry out our work,” he said.

The diver’s mission was to bring oxygen tanks and carry lines along the passageways between a forward operating base and the muddy embankment where the children and coach are sheltering.

Even for expert divers the journey is an exhausting seven-hour round trip.

“It’s very risky (diving out). Think about it, a Navy Seal just passed away last night, so how about a 12-year-old kid,” said Rafael Aroush, an Israeli diver helping the rescue bid.

Officials vowed to investigate the death, and have sent his body to a local hospital for an autopsy.

The incident marks the first major setback for the rescue effort.

Rescuers continue to work to save the Thai boys and their 25-year-old coach from the flooded cave, but some say they may be too weak to complete the terrifying mission.

It is believed 1.5km of the cave is still full of water. The rescue mission will go on despite the death.

The distance between a rescue base camp in side “chamber three” of the cave complex and where the team is stranded is 1.7km. In order to reach the boys from the base, a diver has to carry at least three oxygen tanks to reach them before replacing the tanks again on the way out.

Two of the boys and the coach are suffering from exhaustion through malnutrition, which could make it almost impossible for them to attempt the perilous journey, a Navy source told CNN.

Skilled cave divers are painstakingly teaching them to swim in preparation for a perilous escape, which involves pairing them with trained frogmen and leading them to safety through pitch-black water and narrow passageways.

Officials confirmed some parts of the journey will be walkable.

Rescuers expect the mission to be completed in stages, with the boys who are well enough removed first and those that are too sick left behind.

It takes even experienced divers six to seven hours to complete the round-trip from forward command in the third cave chamber to the boys huddled on a ledge deep inside the complex at Noem Nom Sao. This could mean a fatal delay if anything was to go wrong during the audacious rescue plan.

Engineers are working to install a cable to allow the children to speak to rescuers and their families to improve their morale.

Rescuers have also been transporting food, supplies and first aid into the caves, along with diving equipment to be used by the boys and oxygen “stage” tanks that will be set up every 25 to 50 metres along their route for extra air.

The coach, a former monk who is reported to be struggling after selflessly sacrificing his share of food, could still be charged over the crisis.

Approaching torrential rains also threaten to derail the risky plan to move the boys through the cave system of linked chambers.

The boys’ frightened families are waiting at the cave entrance to be reunited with them.

It is believed the group may have entered as part of an initiation rite, although two mothers came forward to say they did not blame coach Ekkapol Chantawong for their boys’ desperate circumstances.

48 HOURS

Rescuers said on Friday morning the rescue mission needed to be completed within 48 hours.

An anonymous navy source told the ABC three factors were driving the urgency — the water level inside the cave, the amount of oxygen available, and the health of the boys and their coach.

He said rescue co-ordinators faced “tough choices” and differences of opinion were emerging.

Australian Defence Force and Australian Federal Police have been tight-lipped about whether to attempt an extraction or wait, even until the end of the rainy season around October.

The Navy source said boys’ biggest challenge would be a 200m stretch of completely flooded cave that made up part of the 600m section between “Pattaya Beach” and chamber three.

A firefighter who has been working on draining the water said levels in parts of the passage leading to the chamber were still flooded all the way to the ceiling, making diving the only way out.

VOLUNTEERS’ DANGEROUS WATER ERROR

Out in the open air, teams from across the world are working frantically with Thai authorities to overcome potentially deadly challenges and save the boys’ lives.

Volunteers have been helping Thai Navy SEALs to pump water out of the caves, but some unregistered helpers made the situation worse by accidentally pumping water back into the cave, officials told the Bangkok Post.

Operation commander Narongsak Osotthanakorn said the volunteers directed the flow of extracted water into the ground, creating a stream that fed back into Tham Luang cave.

“We are racing against water,” said Mr Narongsak, former governor of Chiang Rai province. “Water is flowing into the cave although we have plugged its channels.”

Mr Narongsak has gave the most detailed description yet of preparations on Thursday.

“This morning (Thursday), I have asked for 13 sets of equipment to be prepared and to check the equipment lists and place them inside in case we have to bring them out in this condition with less than 100 per cent readiness,” said Mr Narongsak at a media briefing.

“For example, if we can accept the 90 per cent safety level, and if all conditions are at that 90 per cent, then we are ready to bring them out. And that’s what we are prepared for.”

Belgian cave diver Ben Reymenants, who owns a business in Phuket, was reportedly exploring a new, wider channel with air pockets that could offer a safer route out for the boys.

If one of them was to panic while following a rope through water like “black coffee”, they could kill themselves or their rescuers.

SPACE EXPLORATION TECHNOLOGY COULD SAVE THEM

Elon Musk has offered to help hone in on the boys’ exact location. Representatives for the Tesla chief executive said they were in talks with Thai authorities about helping in the rescue.

Space Exploration Technologies (Space X) or Boring Company technology would pump water or provide heavy-duty battery packs known as Tesla Powerwalls but it’s unclear whether Thai officials will accept the offer.

In recent days Musk has put forward possible ways his companies could help.

Last year, the Puerto Rico government asked Musk to help after a devastating hurricane hit, with Tesla sending Powerwalls and providing advice on rebuilding the Caribbean island’s infrastructure.

Boring, Musk’s tunnelling start-up, could potentially make available its massive drills or excavation expertise, but such an approach could be too dangerous for this mission.

HIDDEN PASSAGE OR A DEATH-DEFYING JOURNEY

Around 30 teams of jungle trekking rescuers are scouring above ground for a possible “secret passage” to safety, after the boys told divers they heard dogs barking, a rooster crowing and children playing.

If they weren’t hallucinating, it might mean the trapped boys are close to a shaft that rescuers could climb down for a far easier evacuation method.

— Additional reporting AP