The operation to rescue 12 boys and their football coach trapped in a cave in Thailand has begun, officials have said.
The group has been trapped for more than two weeks after monsoon flooding cut off their escape and prevented rescuers from finding them for almost 10 days.
The acting Chiang Rai governor told reporters “today is D-Day” with 13 foreigner and five Thai divers taking part in the rescue.
The operation began at 10am local time (4am BST) on Sunday and he said it would take at least 11 hours for the first person to be rescued.
Thai army commander Major General Chalongchai Chaiyakam said the 13 “will continuously come out in approximately two to four days, which all may change depending on weather and water conditions”.
The only way to bring them out of Tham Luang Nang Non in Chiang Rai province is by navigating dark and tight passageways filled with muddy water and strong currents, as well as oxygen-depleted air.
A former Thai navy SEAL passed out making the dive on Friday and died.
Experienced cave rescue experts consider an underwater escape a last resort, especially with people untrained in diving, as the boys are.
The path out is considered especially complicated because of twists and turns in narrow flooded passages.
But the governor supervising the mission said earlier that mild weather and falling water levels over the last few days had created optimal conditions for an underwater evacuation that will not last if it rains again.
Authorities had said that incoming monsoon rains that could send water levels in the cave rising, coupled with falling oxygen levels in the enclosed space, added to the urgency of getting those trapped out.
Earlier efforts to pump out water from the cave have been set back every time there has been a heavy downpour.
Narongsak said on Saturday that experts told him water from new rain could shrink the unflooded space where the boys are sheltering to just 10 sq m (108 sq ft).
“I confirm that we are at war with water and time from the first day up to today,” he added.
“Finding the boys doesn’t mean we’ve finished our mission. It is only a small battle we’ve won, but the war has not ended. The war ends when we win all three battles — the battles to search, rescue and send them home.”
An update on Saturday from the Thai navy said three navy SEALs were with the boys and their coach, one a doctor.
The 13 were having health evaluations and rehabilitation, and were being taught diving skills. Food, electrolyte drinks, drinking water, medicine and oxygen canisters have been delivered to them.
A major concern of the rescuers is that oxygen levels in their safe space could fall dangerously low.
Rescuers have been unable to extend a hose pumping oxygen all the way to where the boys are, but have brought them some oxygen tanks.