They're climbing rocks, they're getting out and walking. General Kongcheep Tantrawanit said, referring to the area where rescue workers had set up a base.
Now, while no further rescue efforts can be carried out on Sunday, there has been a breakthrough as the boys were retrieved.
In his letter, the 25-year-old coach Ekkapol Chantawong reassured parents, saying: "Dear all kids' parents, now all of them are fine, the rescue team is treating us well. They are now at the field hospital near the cave", said Tossathep Boonthong, chief of Chiang Rai's health department and part of the rescue team.
She said rescuers have not been giving away how optimistic or pessimistic they are. but "it was clear they were tense".
Reporters are ordered to move 2 kilometres back as final rescue preparations began on Sunday at Tham Luang cave in Mae Sai district, Chiang Rai.More news: Emotional Hamilton rises to the occasion with record British GP pole
He said 13 ambulances and multiple helicopters are ready to transport the boys and their coach to hospitals.
Thai officials said 13 foreign and five Thai divers are taking part in the rescue operation. The next phase of the operation is expected to start in 10-20 hours.
Monsoon flooding had initially cut off their escape, and rescuers were unable to find them for more than a week.
The operation to rescue the Thai football team trapped in a cave has begun this morning.More news: Woman arrested after scaling Statue of Liberty in protest
"If we wait and rain water comes in, our readiness will be lower than now", said Narongsak Osottanakorn, governor of Chiang Rai province.
"He added: "They can not decide how many of them will be able to come out for the first operation".
"Today is the D-day". Narongsak said Saturday that experts told him water from new rain could shrink the unflooded space where the boys are sheltering to just 10 square meters (108 square feet).
The earliest the first boys could emerge is 21:00 local time (16:00 GMT) on Sunday, according to officials, who added that both the trapped group and their families had been informed of the plan.
The officials are saying that the entire rescue operation will take 3-4 days to complete and it might get reduced or extended depending on the weather conditions.More news: Iran's Rouhani terms USA threats to end oil imports as a "fantasy"
The soccer team's ordeal has drawn huge media attention in Thailand and overseas, as monsoon conditions worsened amid a frantic search to find the trapped youngsters.