Eight of the 12 boys who had been trapped within the flooded cave were rescued during the first two days of the operation.
The group would be kept under observation in hospital for a week.
The four who were rescued previously were taken to a hospital in Chiang Rai for evaluation.
The first four boys to be freed were reunited with their parents on Monday night through a glass window.
"We have more operating personnel".
"We have more expertise than yesterday", he said.
Four more of the boys were carried on stretchers out of the labyrinthine Tham Luang cave on the Myanmar border at dusk on Monday, bringing to eight the number brought out after two rescue pushes on successive days.
VideoOne of the divers on the rescue team in Thailand explains the difficulty of getting the boys out.
"If nothing goes wrong the remaining boys, the doctor (a Thai Navy Seal medic) and the three (Thai) Navy Seals who have staying with the boys since the beginning of the mission will come out this evening".
However the boys - aged between 12 and 16 - would remain in quarantine until doctors were sure they had not contracted any infections from inside the cave. There was some rain on Sunday, which caused some water to go into the cave, but officials were able to pump an nearly equal amount of water out.More news: Sebastian Vettel spoils Lewis Hamilton's Silverstone party
The eight boys who've been rescued so far have all swum out of the cave, each escorted by two expert divers.
"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. They will be monitored closely to see if they pick up any infectious disease from deep within the cave.
Rescuers are moving ahead quickly because they are afraid monsoon rains will completely flood the caves. "Today is the 10 July 2018". Authorities have said the mission could take up to four days to complete and heavy rain is forecast in the coming days.
Musk tweeted that the pod's design was based on feedback from some of the cave divers in Thailand. He said it was out of respect for the families whose sons were still trapped in the cave. "We believe that we can do even better and it will be a 100 percent success", he said.
The saga has dominated global headlines, with the team spending 9 days unaccounted for inside the cave, before British divers found the emaciated and dishevelled group huddling on a muddy bank above the flooding.
The plan is "set for four people", Osatanakorn said.
The death Friday of a former Thai navy SEAL underscored the risks.
All preparations, including replacing the oxygen cylinders positioned along the route out in the cave, take at least 20 hours, he said.
Authorities on Tuesday were planning for their final push. It is rainy season in Thailand at the moment, with torrential downpours that appear out of nowhere dominating the weather patterns.
Another and perhaps more worrying concern was that oxygen levels in the complex were falling close to unsafe levels.