Although three of those stranded had been described as weakening, Osottanakorn said the team was in relatively good condition overall.
"The kids are still are able to walk around, play around comfortably", he said. "They are happy and they are safe".
Rescuers are also pursuing other options to extract the boys, hoping that finding a shaft or drilling into the mountain in which the cave is located will lead them to a sort of backdoor entrance.
"I'm anxious about the rain", said Visunlaya Songjang, 59, a volunteer from Mae Sai. I will rush to go back.
"The plan that I've held on to from the beginning is that we have to bring the kids out, and the determining factor of this plan is to have as little water as possible", he said. But there are mounting concerns about the oxygen level in the chamber, which officials said had fallen to 15 percent from the usual level of 21 percent.
Bill Whitehouse, of the British Cave Rescue Council, said the death showed just how risky the operation is.
Also, numerous passageways leading to the cave are narrow, and most of the boys do not know how to swim.
The priority, Pasakorn and army officials say, is getting oxygen to the boys as it slowly runs out.
However, the official in immediate charge of the operation, Governor Narongsak Osatanakorn, indicated at a news conference that if heavy rains started and appeared to be causing flooded areas in the cave to rise again, divers would try to take the boys out right away. But Narongsak said it would probably take even longer - until December or January - for the water level to get that low. "We have limited amount of time". "The flawless situation is no water at all, zero, but it's impossible because that only happens in December or January", he said.
"We have to make a clear decision on what we can do", he told the French news agency.
The rescue effort suffered a disheartening setback Friday with the death of a former Thai navy SEAL diving in the flooded passageways to deliver supplies, as authorities raced against worsening weather and lessening oxygen.
Divers Friday night brought out poignant letters written by those trapped inside. "They don't know the Thai people".
"No matter how well prepared they are for this and no matter what they do and the professionalism of those involved, there is going to be an inherent risk with this". "I promise to take the very best care of the kids".
He further discussed ideas over Twitter with James Yenbamroong, CEO of Thai space startup mu Space Corp. on the possible ways that he could work in the rescue mission.
It shows the enormous task ahead for the boys, several of who are weak from not eating proper food for days. The letters, carried by divers making 6-hour trips in each direction, were the first direct communication between the parents and their sons. Grandpa, Uncle, Mum, Dad and siblings, I love you all.
The boys are 11-16 years old and their coach is 25. "Don't blame yourself", their letter to him read. "Thank you for your kind support and I would like to say I'm really sorry to you all", he wrote. "I deeply apologize to the parents".
"Night loves Dad and Mom and brother, don't worry about me". Aunt, please tell grandmother to make a vegetable drink and crispy pork when I get out.