A former Thai navy diver who joined in search efforts to rescue 12 boys and their coach trapped in a flooded cave in Thailand has died.
Saman Gunan, 38, lost consciousness on his way out of the Tham Luang cave complex after delivering supplies and could not be revived.
"His job was to deliver oxygen. He did not have enough on his way back," said an official.
The diver had left the navy but had returned to help with the rescue operation.
"A former SEAL who volunteered to help died last night around 2am," Chiang Rai Deputy Governor Passakorn Boonyaluck told reporters at the rescue site.
Mr Gunan, said to be an avid runner and cyclist, was part of a massive rescue operation which started almost two weeks ago after the group went into the Tham Luang cave.
About 1000 people are involved in the rescue operations, including navy divers, military personnel and civilian volunteers.
The boys were found nine days after they entered the caves in Chiang Rai province following a football training session and became trapped by rising waters caused by heavy rainfall.
Earlier this week, Thai officials told reporters that rescuers were providing health checks and treatment, and keeping the boys entertained, adding that none of those trapped were in a serious condition.
A deluge is expected to hit in a matter of days that could force the water level up, threatening to flood the pocket where the group took refuge.
The region of Chiang Rai where the boys are trapped has for the past few days experienced a dry spell, and rescuers have taken advantage of this to pump water out of the cave complex.
About 128 million litres of water had been pumped out by Thursday, with the water levels coming down at an average rate of 1.5cm per hour. Rescue workers are now able to walk through a 1.5km stretch from the entrance to what's being called the third chamber.
But heavy monsoon rains are forecast for Sunday. Chiang Rai Governor Narongsak Osotthanakorn said they were "racing against water".
"We are calculating how much time we have it if rains, how many hours and days," he said.