While their parents have been able to visit them, they have been kept separate "through the glass because doctors are concerned".
"Everyone is strong in mind and heart", he said at a news conference of officials involved in the high-risk rescue effort.
Thongchai Lertwilairattanapong, a health department inspector, earlier told reporters one from the last group rescued on Tuesday had a lung infection and they were all given vaccinations for rabies and tetanus.
None of the first group of four boys to emerge has a fever, and the two boys that had lung infections are improving. The children would be in the hospital for up to 10 days, the doctor said, adding that they require 30 more days to recover at home.
Thailand celebrated the successful mission to free 12 boys and their football coach from a cave Wednesday, with the nation heaping praise on the rescue team as the triumphant tagline "Hooyah" spread across social media.
The boys and their coach went missing after football practice on June 23, setting out on an adventure to explore the cave complex near the border with Myanmar and celebrate a boy's birthday.
Duangduen Sittiwongsa, a classmate of 16-year-old Pheeraphat "Night" Sompiengjai, whose birthday fell on the same day the team entered the cave, said they would give him cake when he came back to school.
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Negotiations are expected to conclude in October before the United Kingdom leaves the world's largest trading bloc. Bridgen then called the prime minister's promises regarding Brexit negotiations a "pretence and a charade".
The Brits who discovered them were among the elite divers who flew out after the Thai authorities begged the world for help.
Narongsak Osatanakorn, the official overseeing the rescue operation, said the boys should not be blamed for their near tragedy.
The rescue mission which spanned days was a success after everyone was rescued.
Boys rescued from the Thai cave wearing masks and resting in a hospital in Chiang Rai.
"Harry's given his all, his family have given the support and we've given the support as well as an organisation", he said.
Police officers took photographs of each other at the massive cave entrance, as pumps continued to suck out huge volumes of water.
The group became trapped in rising floodwaters and were found nine days later emaciated and disheveled on a muddy ledge, with water lapping ominously below.
The four boys rescued first are "well, they're up and about", Sky News' southeast Asia correspondent, Siobhan Robbins, said. Two divers were helping each one make his way through very small passages filled with water. "Mission accomplished" and the Bangkok Post emblazoned with "All Wild Boars saved".