MAE SAI: Thai rescuers vowed to take a "no risk" approach to freeing 12 boys and their football coach from a flooded cave, as fresh video emerged yesterday showing the team in good spirits following their astonishing discovery nine days after going missing, reports AFP.

Freeing the boys from the still-submerged cave complex is expected to be a protracted process, fraught with challenges for a group who are not divers and some of whom are believed to be unable to swim.

With a country engrossed in the rescue mission, authorities insist they will only move the boys once their safety can be guaranteed, even though monsoon rains are predicted to soon resume. "We have to be 100 percent confident that there is no risk to the boys before we evacuate," Narongsak Osottanakorn, Chiang Rai provincial governor, told reporters on Wednesday.

"We will take care of them like they are our own children," he said.

The group are being taught how to use diving masks and breathing apparatus, he added, but from the safety of the muddy bank which for now remains their sanctuary.

Authorities are also pumping out water round-the-clock aware of the bad weather forecast in the days ahead, removing around one centimetre each hour in a massive draining operation. "We want to evacuate all 13 people as soon as possible but I don't want to specify day and date," Thailand's junta leader Prayut Chan-O-Cha said later.

In a heartening message to families waiting in outside the cave, footage was released by the Thai Navy SEAL featuring 11 of the 12-strong team. Each made a traditional Thai greeting gesture to the camera before introducing themselves by their nickname and saying "I'm in good health".

Several of the boys in the frame are wearing protective foil blankets and are accompanied by a smiling diver in a wetsuit.

Also seen is the 25-year-old coach, who went with the boys down the cave after football training on June 23.

A one-minute video clip ends on a jovial note, with one of the 12 young footballers saying he was forgotten in the round of introductions, sparking laughter.

The images have delighted a Thai nation that has held its breath for a successful outcome to a challenging rescue kilometres inside one of the country's longest caves.

In the video the boys, who have spent 11 nights underground, appear relaxed and much more alert than when they were when British divers found them late Monday huddling on a muddy ledge above surging underground waters.