An ambulance exits from the Tham Luang cave area as operations continue for the eight boys and their coach still trapped at the cave in Khun Nam Nang Non Forest Park in the Mae Sai district.
The group of 12 boys and their coach Ekapol Chantawong had gone to explore the Tham Luang cave in northern Chiang Rai province on June 23 after their football practice.
The dramatic and unsafe rescue was launched on Sunday and four boys were brought out that day.
The head of the rescue mission, Narongsak Osottanakorn, announced late on Sunday the first four children were brought out safely.
A source involved in the rescue mission who saw two of the four boys walk out of the cave told Reuters that they looked exhausted but healthy, adding that one even looked "vivacious and fresh". But the rains stopped on Monday, and the mission resumed at 11 a.m. local time. Narongsak said experts told him the new rain could shrink the unflooded space where the boys are sheltering to 108 square feet.
Trained divers are taking about five hours to get from the cave's entrance to where the boys are trapped - one way.
"This morning they said they were hungry and wanted to eat khao pad grapao", Narongsak said, referring to a Thai dish of meat fried with chili and basil and served over rice. So the sub still could come into play on a third day of rescues. Crews will have to replenish air tanks along the route before rescuing the others.
The first four boys were rescued on Sunday and are in a stable condition in hospital, although their families say they haven't been allowed to see them yet due to fear of infection. He said officials were meeting Monday morning about conducting the next stage of the operation. Musk said his submarine has eight handles, four in the front and four in the rear, and four air tank connections. It took mere hours for them to devise a plan.
Narongsak explained the group made a decision to move forward with the mission because heavy rains are expected in the area in the coming days, which could have further complicated the rescue.
Around 20 Australians have been involved in rescue efforts to free 12 boys and their soccer coach from a Thai cave. They were stranded by flash floods that caused water levels to rise, making it hard to get out.
The dozen boys between the ages of 11 and 16 are accompanied by their 25-year-old coach.
Thailand's Meteorological Department said there was a 60 percent chance of rain Monday with thunderstorms forecast throughout the week.
The rescue operation is estimated to take ten hours, and end by 9 p.m.
On Sunday, Musk tweeted a series of videos showing a team of divers testing the pod in the swimming pool at Palisades Charter High School. If the tests are successful, the sub would be placed on a 17-hour flight to Thailand.
Experienced cave rescue experts consider an underwater escape a last resort, especially with people untrained in diving, as the boys are.
The saga has dominated global headlines, with the team spending nine days unaccounted for inside the cave, before British divers found the emaciated and dishevelled group huddling on a muddy bank above the flooding.
After Musk received an outpouring of gratitude for his rescue plans, he replied: "Thanks, we've not done anything useful yet".
On Sunday, divers held the first four boys close to bring them out, and each had to wear an oxygen mask to enable normal breathing, authorities said.