In this undated photo released by Royal Thai Navy on Saturday, July 7, 2018, Thai rescue team members walk inside a cave where 12 boys and their soccer coach have been trapped since June 23, in Mae Sai, Chiang Rai province, northern Thailand.
They were guided by expert divers who plotted the hours-long escape through more than four kilometres (2.5 miles) of twisting passageways and flooded chambers.
Four of the boys were rescued from the Tham Luang Cave complex last night and are now recovering in Chiang Rai hospital after their 16-day ordeal.
"I am still waiting here at the cave, keeping my fingers crossed to see whether my son will be one of those to come out today", Akkarat Wongsukjan, a mother of Pheerapat - known by his nickname "Night" - told AFP.
But experts have warned that extraction efforts will bear significant risk, underscored by the death of a retired Thai Navy SEAL early Friday morning when he ran out of oxygen during a dive.
Divers are set to resume their rescue of a Thai soccer team trapped inside a flooded cave later today, after earlier swimming four of the boys - including the weakest child - to safety.
The rescue mission began on Sunday morning, almost a week since the 12 boys, aged 11-16, and their coach had been discovered on an embankment 2.5 miles (4 kilometers) inside the winding tunnels. The boys are between 11 and 16 years old.
Who are the boys and their coach?
But Narongsak said earlier that recent mild weather and falling water levels had created optimal conditions for an underwater evacuation. Chiang Rai acting Gov. Narongsak Osatanakorn said two divers will accompany each boy as they are led out of the cave.
The group was found dishevelled and hungry by British cave diving specialists nine days after they ventured in.
The operation, which started on Sunday morning, will take two to three days to complete, as each round trip from the rescue camp in the cave to the site where the boys and their coach are located takes 11 hours.
A risky mission to rescue 12 Thai schoolboys and their soccer coach trapped inside a flooded cave for more than two weeks began on Sunday.
The potential for rising water and the dwindling oxygen levels added to the urgency of getting the team out.
"We will still maintain our planned mission and the two main obstacles are time and water", a spokesperson said. He has also thanked worldwide experts who helped find the boys.
The boys, all members of a local soccer team called the Wild Boars, had been hiking in the caves when they became trapped by rain waters. It was not immediately known if a US diver was among them. "I had been anxious about my son, that he would be exhausted, he would be tired", he said.
One particularly touching note from another boy said: "I'm doing fine, but the air is a little cold, but don't worry".