A former Navy Seal diver has died while taking part in the rescue mission for 12 boys and a football coach who have been trapped in a Thai cave for two weeks.
The death of Samarn Gunan has highlighted the dangers of the tense rescue operation, with the boys trapped 2.5miles (4km) within the complex network of waterlogged caves.
One of the options to free the boys is teaching them to dive, but even experienced divers have found its currents and tight passages extremely challenging.
Thai diver Mr Gunan had been working as a volunteer during an overnight mission in which he had been delivering oxygen canisters in the Tham Luang cave system, according to authorities.
Samarn Gunan was an ex Thai Navy diver
“On his way back he lost consciousness,” Thai Seal commander Apakorn Yookongkaew said, adding that a diving partner had tried to help bring him out.
“But even though we have lost one man, we still have faith to carry out our work.”
Rescue teams are now battling against the clock to beat monsoon rains expected on Saturday, having reduced water levels in the cave by 40%.
Rescuers are racing against time to rescue the boys and their coach The boys, aged 11 to 16, and their coach were found on Monday, after they went missing following a football game on 23 June.
The moment a British diver encountered the boys and their 25-year-old coach after 10 days in the cave was captured on film, with one of the youngsters asking the rescuers what day of the week it was.
Parts of the passageway leading to where the group were found are still flooded all the way to the ceiling – leaving diving out of the cave the only option for survival.
A graphic showing the boys’ predicament
Officials have said not all 13 of those trapped may be extracted at the same time depending on their condition, and the boys have been practising wearing diving masks and breathing.