"But I guarantee they will all be safe", he added, reflecting an increasingly bullish attitude after two successful operations so far.
The plight of the boys and their coach has drawn worldwide attention since they became trapped when they went into the cave after soccer practice on June 23.
The plight of the boys and their coach has riveted Thailand and much of the world - from the heart-sinking news they were missing to the first flickering video of the huddle of anxious yet smiling boys when they were found 10 days later by a pair of British divers.
Fortunately, Thai authorities said the rain that fell late Sunday and early Monday did not change the water level in the cave in Mae Sai, Thailand, where the boys and coach are trapped.
VideoOne of the divers on the rescue team in Thailand explains the difficulty of getting the boys out.
Officials were not immediately available to comment on who had been brought out, and their condition was unclear.More news: U.S. threatens nations over world breastfeeding resolution, shocking health officials
Harris played a pivotal role in the rescue effort, positioned on the muddy bank in the cave with the boys and their coach, assessing their fitness for the perilous journey back to the outside.
"We have not been told which child has been brought out ..."
All eight boys, aged between 12 and 16, are being treated in an isolation ward in Chiang Rai Prachanukroh hospital. Some had infections but otherwise all of them were in good health.
Jesada said the group had been given x-rays and blood tests, adding that two presented suspected symptoms of pneumonia but were given antibiotics and were "in a normal state". However, scattered monsoon rains continued to risk percolating through the limestone cave walls to flood the tunnels with fast-flowing water.
"Today (Tuesday) we hope to be faster", Narongsak added, of the complex and unsafe operation that involves diving through narrow, flooded chambers.
Manning paid tribute to former Thai Navy SEAL Saman Kunan, who died after delivering oxygen tanks in the cave.More news: Game of Thrones racks up 22 Emmy nominations
Torrential rain fell overnight and through the morning in the area of the Tham Luang cave complex, where the Wild Boars youth soccer team had been stranded on June 23.
Two of the boys had suspected lung infections but the four boys from the first group rescued were all walking around their beds.
The rescued boys are still being held in quarantine while lab tests are being done and have not been able to have direct contact with their parents yet.
Rescued schoolboys are moved from a military helicopter to an awaiting ambulance at a military airport in Chiang Rai, Thailand, July 9, 2018.
Elon Musk visited the flooded Thailand cave to offer a "kid-sized" submarine to help with the rescue - only to be told his technology wasn't "practical" to the mission.
"Mini sub arriving in about 17 hours", Musk tweeted Sunday.More news: Croatia fans display banner in downtown Moscow