Video provided by the Thai Navy Seal shows the boys and their soccer coach as they are rescued in a cave.
Video provided by the Thai Navy Seal shows the boys and their soccer coach as they are rescued in a cave.
A cave explorer assisting Thai authorities trying to rescue 12 trapped schoolboys believes "we'll know in the next 24 hours" if they will live or die.
British cave expert Vern Unsworth, who lives in Thailand, said the conditions were getting worse and there was now a narrow window in which the group could escape.
"I think we'll know in the next 24 hours...We'll keep our fingers crossed - everybody needs to pray and hope for a good outcome," Mr Unsworth told the BBC.
The boys aged between 11 and 16, along with their football coach, have been trapped in the flooded Tham Luang cave system for 12 days.
But heavy monsoon rain is coming, and Mr Unsworth said rain that had already fallen had caused a dramatic rise in water levels in the cave.
"The main thing is to try to get the children to safety. We have to keep hoping. The water levels are rising, we had a lot of rain overnight."
He said the temperature of the water was cold, although the air temperature wasn't an issue.
Time is of the essence for rescuers.
The challenge ahead of the group is enormous - none of them are divers and some can't even swim. They have also been weak after spending days without food, but are gaining in strength after being given high-protein drinks.
Authorities insist they won't begin the rescue mission that has gripped the whole world until it was safe to do so. It will be dawn there at about 8.30am AEST.
"We have to be 100 per cent confident that there is no risk to the boys before we evacuate," Narongsak Osottanakorn, Chiang Rai provincial governor, told reporters.
"We will take care of them like they are our own children," he said. The group are being taught how to use diving masks and breathing apparatus, he added, but from the safety of the muddy bank which for now remains their sanctuary.
Getting out of the cave won't be easy. It will require diving of about a kilometre which could not be completed all at once. In total, it was expected to take three hours.
Another British expert, Gary Mitchell, described the challenging conditions. "There's air pockets along the way," he told the Associated Press.
"It's confined spaces. It's almost zero visibility. There's currents to battle against in places as well. So it's a really quite a strenuous environment to be in."
Doctors and nurses were seen moving up to the entrance of the flooded cave last night, fuelling speculation that an attempt was imminent.
Medical staff were filmed leaving the staging area further down the slope and were on the move to the mouth of the cave as reports emerged the rescue mission could begin as soon as this morning.
The football team.
Dive lessons
Classmates and friends of the schoolboys also reportedly were near the cave's entrance singing songs of support.
After a day of sustained pumping efforts, water levels inside the massive cave complex have ben reduced and fierce currents have eased, The Australian reports.
However, that was before the rain that lashed the area yesterday afternoon.
The newspaper reports it has been told that fast-water currents inside the cave have eased to a standstill and with monsoonal rains expected to resume by Friday, conditions for the rescue are as good as they are likely to get.
Royal Thai Navy SEALs have been teaching the boys and their coach — none of whom can swim — how to breathe in a full face scuba mask.
But officials have warned not all of the 12 schoolboys, and their coach, may be able to come out of the cave at the same time.
Chiang Rai provincial governor Narongsak Osatanakorn said yesterday that "all 13 may not come out at the same time".
"If the condition is right and if that person is ready 100 per cent, he can come out," he said.
Thai authorities have been working with Navy SEALs to run a fibre optic internet line into the flooded cave so that phone calls can be made in and out.
New video of laughing boys
Despite the imminent danger, the children have appeared in a new video, laughing as they greet the camera to say they are in good health.
The footage, published by the Thai Navy SEAL Facebook page, runs by 11 of the 13 members of the team, each makes a traditional Thai greeting gesture to the camera before introducing themselves by nickname and saying "I'm in good health".
Some appeared to be wearing a change of clothes since they were found late Monday and most were wrapped in foil warming blankets.
The 12 schoolboys in baggy football kits and their coach were discovered yesterday to jubilant celebrations, but it was warned that the rescue operation to guide them through the cave's 2km system could take up to four months.
The reason the boys entered the cave, according to a Dutch diver working in Thailand, was to write their names on the wall as part of an initiation ritual.
Sky News reported that Dutch diver Ben Reymenants, who runs a diving school in Phuket, had made contact with the boys.
He said when the boys ventured into the Tham Luang Nang Non cave complex to write their names on the walls, a flash flood trapped them..
"They left their backpacks and their shoes before wading in there, trying to go to the end of the tunnel like an initiation for local young boys," he said.
Rescue options
The cave system is nearly 2km long.
The Interior Minister Anupong Paojinda said evacuating the boys "must speed up" as soon as possible before more rain falls and exacerbates the flooding.
The grim forecast could force authorities to have the children — who cannot swim — out through a narrow, underwater passage in the cave.
"If something happens midway, it could be life-threatening." Mr Paojinda said.
"Diving is not easy. For people who have never done it, it will be difficult, unlike diving in a swimming pool, because the cave's features have small channels."
There are a couple of other options on the table if that doesn't work and the heavy rains subside.
Authorities are considering digging them out of the cave, but if this goes wrong it could cause the cavern where the team has taken refuge to cave in.
Rescuers could potentially drain the caves enough to allow the boys to wade or float out with life vests.
The final option is to leave them in there for three or four months until the rains subside is also being considered.
The group of 13, who disappeared when flooding trapped them in the cave they were exploring on June 23 after a soccer game, were found by rescue divers late Monday night in the cavern in northern Chiang Rai province during a desperate search.
The effort drew international help and has riveted Thailand.
Detective Superintendent Thomas Hester said the team of six divers from the Australian Federal Police faced "incredibly challenging" conditions.
Rescuers have asked for 15 small and extra small full face masks, leading to speculation that divers were preparing a rescue mission through the 750-metre flooded stretch of the Tham Luang Nang Non cave.
Media have been told it was too dangerous to use conventional breathing apparatus as it could easily be knocked out during the dive.
The boys, aged 11-16, and their 25-year-old coach were described as healthy and being looked after by seven members of the Thai navy SEALs, including medics, who were staying with them inside the cave. They were mostly in stable condition and have received high-protein drinks.
It has been revealed that the boys visited the cave to attempt a local initiation rite in which they had to scrawl their names on a wall at the end of the tunnel.
While efforts to pump out floodwaters are continuing, it's clear that some areas of the sprawling cavern cannot be drained, said Mr Paojinda, a member of Thailand's ruling military junta.
In order to get them out ahead of the bad weather forecast for later in the week, they might need to use diving gear while being guided by professional divers, he said.
Mr Anupong said the boys would be brought out via the same complicated route through which their rescuers entered, and he conceded that if something went awry, it could be disastrous.
Yesterday, a video released by the Thai navy showed the boys in their soccer uniforms sitting in a dry area inside the Tham Luang Nang Non cave above the water as a light held by a rescuer was shone on their faces.
Cave rescue experts have said it could be safer to simply supply them where they are for now, rather than trying to have the boys dive out. That could take months, however, given that Thailand's rainy season typically lasts through October.
SEAL commander Rear Adm. Arpakorn Yookongkaew said there was no rush to bring them out, since they're safe where they are.
"We have given the boys food, starting from easily digested and high-powered food with enough minerals," Arpakorn told a news conference.
Having them dive out of the cave was one of several options being considered, "but if we are using this plan, we have to be certain that it will work and have to have a drill to make sure that it's 100 per cent safe," he said.
