Rescuers in Thailand are racing against the weather to free 12 boys and their football coach trapped in a flooded cave in Thailand.
Heavy rains are expected to hit in a matter of days and could see water levels rise, threatening the area where the group has taken refuge.
The region of Chiang Rai has for the past few days experienced a brief window of dry weather.
Rescuers are now considering how best to bring the group to safety.
“We are racing against time before we found them,” Chiang Rai Governor Narongsak Osotthanakorn said at a press conference on Thursday morning. “Now we are racing against water.”
If the rain stops for long enough, there is a possibility that the group could walk out of the Tham Luang cave complex, rather than having to dive.
The total journey from the cave’s entrance to the trapped group currently takes a total of 11 hours – six hours in and five hours back out.
Many of the boys can’t swim, and all will have to be taught basic diving skills if they are to leave that way.
‘The boys are my brothers’
Helier Cheung, BBC News, Tham Luang cave
Rescue teams are working in extremely difficult conditions. The heat has been sweltering and unrelenting, at over 30C, while much of the site is submerged in squelchy mud that is several inches thick in places and extremely slippery.
But the work has continued at an unrelenting pace – as everyone is aware that, once the monsoon rains start, rescue efforts will be much more difficult.
Meanwhile, hundreds of workers are helping to keep the site in order, with road engineers laying gravel to try and secure the mud, workers for the Thai royal kitchen providing hot food for everyone, and volunteers handing out water bottles and ice lollies to those on site.
One local civil servant, who had volunteered to help hand out supplies, said he did not know the boys personally but had decided to help because “I consider the boys in the caves as my brothers”.
The Thai military has previously said that if they can’t dive out, the group may have to wait up to four months for flooding to recede before they can leave.
Food and other supplies are being put in place for that outcome.
Interior Minister Anupong Paojinda later stressed the urgency of the evacuation, adding that rain was forecast “in the next few days”, the Bangkok Post reported.
Attempts are being made to reduce the risk of further flooding by pumping water from the cave system, Mr Anupong said.
Water levels have dropped by more than 40cm (15in) since Wednesday, with rescue workers now able to walk through a 1.5km (0.9 mile) stretch from the entrance to what’s being called the third chamber.
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.
The boys, aged between 11 and 16, and their 25-year-old coach went missing on 23 June. It is believed they entered the cave when it was dry and sudden heavy rains blocked the exit.
They were found on a rock shelf about 4km (2.5 miles) from the mouth of the cave on Monday night by two British rescuer divers.
The cave complex is regularly flooded during the rainy season which lasts until September or October.