Operation started 10am local time and the soonest any boy will be freed is 9pm local time • Thai cave rescue under way: officials announce mission has begun - live updates 
 
 Eighteen divers have entered a cave in northern Thailand in an attempt to retrieve 12 boys and their football coach who have been stranded in a cave for the past two weeks. 
 
 The rescue operation started about 10am local time and the soonest any boy would be freed was 9pm (3pm BST), said Narongsak Osatanakorn, the head of the joint command centre coordinating the rescue. 
 
 The boys would be removed gradually with each accompanied by two divers in an operation that could continue until at least Monday. 
 
 “Today we are most ready,” Osatanakorn told a press briefing. “Today is D-Day.” 
 
 The team includes 13 international divers and five Thai navy Seals. “We can say they are all international all-stars involved in this diving operation and we selected five of our best who can work with them,” he said. 
 
 The first 10 members of the international team entered the cave at about 10am local time with some heading for the muddy slope where the boys are sheltering and others stationed a few hundred metres away at an area called Monk’s Junction. 
 
 A second group of three foreign divers entered at about 2pm “to support diving efforts”, according to a statement issued by the command centre, with additional rescuers in place helping to operate a rope system in a difficult middle stretch of the track. 
 
 An Australian doctor with extensive cave-diving experience, Dr Richard Harris, went into the chamber on Saturday, examined the boys and approved them for the operation, authorities said. He is also part of Sunday’s operation. 
 
 Authorities said the number of boys that would exit the cave in the first batch would be decided in consultation with doctors. “The divers will work with medics in the cave to assess the boys’ health before determining who will come out first,” they said in a statement. 
 
 The boys and their families have been informed. “Their health and their minds are ready and they all have knowledge of the mission,” Osatanakorn said. “They’re ready to go out.” 
 
 He said the 1.5km path from the cave entrance to the “third chamber” that has been a staging ground for the operation was not completely dry but mostly walkable. “Yesterday the water levels were the lowest they had been,” he said. 
 
 Parents of boys trapped in Thai cave tell coach: don't blame yourself Read more 
 
 “Although there are some slightly difficult parts [where] we have to bend or crawl, we can say that we can just walk through it.” 
 
 He would not say whether the boys would need to dive at all in the 1.7km journey from where they are sheltering to the third chamber. “What I can tell you is that there are many parts that they can walk,” he said. 
 
 Water levels had dropped 30cm since Saturday and “we have reached peak readiness,” he said. “The meaning of readiness is ... perfect weather, water and the kids’ readiness, physical and mental.” 
 
 
 
 A return journey from the boys’ chamber to the exit takes about 11 hours and the rescue chief said the entire mission could take at least two days. “There’s no time limit for the operation,” he said. “It depends on the weather. It depends on the water levels. If something changes we’ll stop. But I expect the operation to finish in the next couple of days.” 
 
 Helicopters are stationed around the cave along with more than a dozen ambulances. Under plans devised earlier this week, each boy will be accompanied on the journey to the hospital by a parent and a mental health worker. 
 
 Authorities had said on Saturday they had a three- to four-day window to remove the boys before monsoon rain risked sealing them off until as late as January. 
 
 But heavy rain hit the site overnight and on Sunday morning media were cleared from the area surrounding the cave, triggering speculation the operation had commenced. 
 
 Authorities said the rainwater overnight was less than expected and did not substantially alter water levels, which have fallen at least 70cm this week due to hundreds of pumps operating inside the cave. 
 
 “We took this chance as our D-day as it is the day that we are very ready,” Osatanakorn said. “We may lose this opportunity, this window to launch the mission. That’s why we decided to do it at 10am today.” 
 
 The boys entered the cave with their football coach on 23 June and became trapped when water inside rose suddenly. They were found on Monday and the Thai military, aided by international experts, have been working on plans to free them from the cave complex ever since. 
 
 Rescuers need to bring them out before the monsoon rains hit, pushing water levels inside the cave up again and trapping them inside for at least four months. ||||| A few minutes after operation chief Narongsak Osatanakorn addressed the media, heavy rain began falling over the press centre, where hundreds of journalists are working to report this latest chapter in the the Tham Luang saga. 
 
 With raincoats draped over heads and computers, we feel just a fraction of the urgency that rescue workers must be feeling as water - the element that started this mess - continues to hamper the rescue effort. ||||| Media playback is unsupported on your device Media caption There were cheers and applause as the first boys' rescue was confirmed 
 
 The operation to free 12 boys and their coach trapped in a cave in northern Thailand is running "smoothly", the head of the operation says. 
 
 Four boys have been brought above ground so far in good health, rescuers say. 
 
 The mission has now been paused for at least 10 hours as air tanks need to be replaced. 
 
 Rescuers decided to go ahead with the hazardous operation on Sunday because of fears of rising waters. 
 
 The next phase would begin on Monday morning, after relaying "all of the air tanks and all systems along the way", Chiang Rai Governor Narongsak Osottanakorn said. 
 
 He corrected earlier reports that said six boys had been freed. 
 
 Divers have been guiding the boys through darkness and submerged passageways towards the mouth of the Tham Luang cave system. They have reportedly been able to make the last part of the journey on foot. 
 
 Rescuers took advantage of a break in the rain to launch the mission much earlier than originally expected. 
 
 The first phase has also been conducted much faster than officials had predicted. 
 
 Media playback is unsupported on your device Media caption Child psychiatrist: "It will be a challenge for these children to go back to normal life" 
 
 The group and their families had all given their agreement that they should be moved as soon as possible, said Mr Narongsak. 
 
 What is happening at the cave? 
 
 A team of 90 expert divers - 40 from Thailand and 50 from overseas - has been working in the cave system. 
 
 Image copyright EPA Image caption An ambulance arrives at a nearby hospital after leaving the cave site 
 
 Getting to and from where the boys are has been an exhausting round trip, even for the experienced divers. 
 
 The process includes a mixture of walking, wading, climbing and diving along guide ropes already in place. 
 
 Wearing full-face masks, which are easier for novice divers than traditional respirators, each boy is being accompanied by two divers, who also carry his air supply. 
 
 The toughest section is about halfway out at a section named "T-Junction", which is so tight the divers have to take off their air tanks to get through. 
 
 Beyond that a cavern - called Chamber 3 - has been turned into a forward base for the divers. 
 
 There the boys can rest before making the last, easier walk out to the entrance. They are then taken to hospital in Chiang Rai. 
 
 In an indication of how dangerous the journey can be, a former Thai navy diver died in the caves on Friday. Saman Gunan was returning from a mission to provide the group with air tanks when he ran out of oxygen. 
 
 He lost consciousness and could not be revived. His colleagues said they would "not let the sacrifice of our friend go to waste". 
 
 Sense of remaining unease 
 
 BBC's Nick Beake at the scene 
 
 This is a hugely high-profile rescue attempt and Thailand knows the world is watching. It has embarked on a dangerous option but believes it's the best for bringing the group out alive. 
 
 It has assembled a team of internationally renowned divers and so far their expertise has brought four boys - thought to be the weakest - back to their families. 
 
 But the relief of those mums and dads will be tempered by the knowledge that nine other families face an anxious wait for the turn of their loved ones to be shepherded through the narrow and murky corridors of the Tham Luang cave complex. 
 
 As one diving expert put it to me, when underwater cave rescues go wrong they go wrong in a big way. So despite this promising start, there is a sense of unease here in Chiang Mai. But the overriding impression from the rescuers is a clear focus and unshakable resolve to finish the job. 
 
 Who are the boys and their coach? 
 
 Chanin Vibulrungruang , 11 (Nickname: Titan) - started playing football aged seven 
 
 , 11 (Nickname: Titan) - started playing football aged seven Panumas Sangdee , 13 (Nickname: Mig), wrote to his parents: "The Navy Seals are taking good care of me" 
 
 , 13 (Nickname: Mig), wrote to his parents: "The Navy Seals are taking good care of me" Duganpet Promtep , 13 (Nickname: Dom) - captain of the Wild Boars, reportedly scouted by several Thai professional clubs 
 
 , 13 (Nickname: Dom) - captain of the Wild Boars, reportedly scouted by several Thai professional clubs Somepong Jaiwong , 13 (nickname: Pong) - reportedly dreams of playing for the Thai national team 
 
 , 13 (nickname: Pong) - reportedly dreams of playing for the Thai national team Mongkol Booneiam , 13 (nickname: Mark) - described by his teacher as a "very respectful and good child" 
 
 , 13 (nickname: Mark) - described by his teacher as a "very respectful and good child" Nattawut Takamrong , 14 (nickname: Tern) - told his parents not to worry about him 
 
 , 14 (nickname: Tern) - told his parents not to worry about him Ekarat Wongsukchan , 14 (nickname: Bew) - promised his mother he would help her at the shop once he was rescued 
 
 , 14 (nickname: Bew) - promised his mother he would help her at the shop once he was rescued Adul Sam-on , 14 - member of a volleyball team that came second in the North Thailand-wide tournament 
 
 , 14 - member of a volleyball team that came second in the North Thailand-wide tournament Prajak Sutham , 15 (nickname: Note) - described by family friends as a "smart, quiet guy" 
 
 , 15 (nickname: Note) - described by family friends as a "smart, quiet guy" Pipat Pho , 15 (nickname: Nick) - wrote in his letter he wanted his parents to take him for barbecued food once rescued 
 
 , 15 (nickname: Nick) - wrote in his letter he wanted his parents to take him for barbecued food once rescued Pornchai Kamluang , 16 (nickname: Tee) - told his parents "don't worry, I'm very happy" 
 
 , 16 (nickname: Tee) - told his parents "don't worry, I'm very happy" Peerapat Sompiangjai , 17 (nickname: Night) - it was his birthday the day the boys went missing, and his parents have told him they are still waiting to hold his birthday party 
 
 , 17 (nickname: Night) - it was his birthday the day the boys went missing, and his parents have told him they are still waiting to hold his birthday party Assistant coach Ekapol Chantawong (nickname Ake), 25 - apologised in his letter to the parents, but they replied that they did not blame him 
 
 How did the group get there? 
 
 The boys were found inside the cave by British rescue divers on Monday, about 4km (2.5 miles) from the cave mouth. 
 
 Aged between 11 and 17, they belong to a football club called the Wild Boars, and became trapped during an excursion with their coach. 
 
 It took nine days to find them in the underground network's dark depths. 
 
 Race against the rain 
 
 Officials had originally thought the group might have to stay where they were until the rainy season ended - and that could have meant months underground. 
 
 They had also been exploring whether they could drill down into the cave, as well as scouring the mountainside for another way in. 
 
 But with the rainy season just beginning, it has become clear that the flooding which originally trapped the boys will only get worse in the coming days. 
 
 Media playback is unsupported on your device Media caption Thailand cave rescue: Meet the volunteer helpers 
 
 Rescuers have been desperately pumping water out of the cave, and Mr Narongsak said on Sunday that water levels inside were at their lowest levels so far. 
 
 "There is no other day that we are more ready than today," he said. ||||| Image copyright Getty Images Image caption The boys, aged between 11 and 17, have been trapped with their coach since 23 June 
 
 Rescuers in Thailand have begun a hazardous operation to lead 12 boys and one adult out of a cave where they have been trapped for two weeks. 
 
 The group are stranded on a ledge 4km inside the Tham Luang cave but amid fears of rising waters, officials have decided they cannot wait any longer. 
 
 Officials have called it D-Day, saying the boys are fit and ready to move. 
 
 Late on Sunday, local reports said the first two members of the group had been brought out to safety. 
 
 It is unclear how long the whole mission will take. 
 
 The boys are being rescued in groups. Expert divers are guiding them out through darkness and submerged passageways towards the mouth of the cave. 
 
 What is happening at the cave? 
 
 A huge volunteer and media operation has built up around the mouth of the cave over the past week. 
 
 Media playback is unsupported on your device Media caption Rescue teams have begun the operation to extract the boys from the cave 
 
 But early on Sunday, journalists were told they had to move down the road, sparking speculation that a rescue mission was about to begin. 
 
 Narongsak Osottanakorn, who has been leading the operation, then confirmed that 18 divers had gone in to get the boys. 
 
 "This is D-Day," he said. "The boys are ready to face any challenges." 
 
 He added that the boys had all been assessed by a doctor and were "very fit physically and mentally... They are determined and focused". 
 
 The group and their families had all given their agreement that they should be moved as soon as possible, he said. 
 
 Why are they acting now? 
 
 Officials had originally thought the group might have to stay where they were until the rainy season ended - that could have meant months underground. 
 
 They'd also been exploring whether they could drill down into the cave, as well as scouring the mountainside for another way in. 
 
 Image copyright Reuters Image caption At a church in Chiang Rai, local people spent Sunday morning praying for the trapped boys 
 
 But with the rainy season just beginning, it's become clear that the flooding which originally trapped the boys will only get worse in the coming days. 
 
 Rescuers have been desperately pumping water out of the cave, and Mr Narongsak said on Sunday that water levels inside were at their lowest levels so far. 
 
 "There is no other day that we are more ready than today," said Mr Narongsak. "Otherwise we will lose the opportunity." 
 
 How will they bring them out? 
 
 Getting to and from where the boys are has been an exhausting 11-hour round trip even for the experienced divers. 
 
 When the operation began, officials said the earliest the boys were likely to reach the surface was 21:00 local time (14:00 GMT) on Sunday. One official has said it could take two to three days to get them all out. 
 
 They'll have to do a mixture of walking, wading, climbing and diving - all in complete darkness - along guide ropes already in place. 
 
 Wearing full-face masks, which are easier for novice divers than traditional respirators, each boy will be accompanied by two divers who will also carry their air supply. 
 
 The toughest section is about halfway out - they'll reach section called "T-Junction", which is so tight the divers will have to take off their air tanks to get through. 
 
 Eventually they'll reach Chamber 3, the cavern which has been turned into a forward base for the divers. They'll rest there before making the last, easier walk out to the entrance. They're expecting to be taken straight to hospital in Chiang Rai town. 
 
 In an indication of quite how dangerous the journey will be, a former Thai navy diver died in the caves earlier this week. Saman Gunan was returning from a mission to provide the group with air tanks. 
 
 He lost consciousness and could not be revived. His colleagues have said they "will not let the sacrifice of our friend go to waste". 
 
 Sense of anticipation 
 
 By Helier Cheung, Tham Luang cave 
 
 This is the moment that everyone has been waiting for - and that some thought would never begin. 
 
 Earlier on, the mood around the rescue sites had been upbeat once the boys were found alive. Smiling volunteers would hand out snacks, or offer massages, to those on the site. 
 
 Now security to the site has been beefed up even more. Several police vans, military officers and ambulances have been entering and exiting the site. There's a solemn sense of anticipation in the air. 
 
 Family and friends of the boys will be getting little rest until they learn the outcome of the rescue operation. 
 
 Why did they go into the cave? 
 
 The boys, all part of the same Wild Boars football team, are aged between 11 and 17 and know the local area well. 
 
 Media playback is unsupported on your device Media caption Thailand cave rescue: Meet the volunteer helpers 
 
 It's thought they went in there on 12 June after training as a fun outing, to celebrate one of the boy's birthdays. They took in only basic food. 
 
 But it appears they went in too far at the wrong time of year, and unexpectedly got cut off. 
 
 Against all odds, they were found by rescue divers early last week, perched on a high ledge in the darkness. 
 
 They were hungry and scared but in remarkably good shape given their ordeal. 
 
 Since then, they've been kept company by navy divers at all times, and had food, light and medical care sent in. 
 
 They even managed to send letters home telling their parents not to worry, but that they were looking forward to coming home.
– "There is no other day that we are more ready than today," rescue director Narongsak Osottanakorn said, in announcing that 18 divers had gone in to rescue the Thai soccer team trapped in a cave since late June. "Otherwise we will lose the opportunity." Now, the BBC reports that four boys have emerged from the cave (or six, per Reuters) and been taken to the hospital. The operation has been put on hold for at least 10 hours because "we've used all the oxygen," Narongsak tells the Guardian. "For the next operation to happen, we cannot say. It will be between 10 and 20 hours, but not over 20. But we have to evaluate all the factors. Air tanks must be put back into place." After a deluge of rain overnight, officials feared worsening flooding in coming days would close the window to rescue the boys and their coach. The mission is an ordeal that could easily last into Monday, notes the BBC: Each boy is being accompanied out by two divers, one of which carries his oxygen, through a darkened journey that includes "walking, wading, climbing, and diving." A doctor examined the boys earlier Sunday, notes the Guardian, and gave the greenlight for the rescue. "This is D-Day," said Osottanakorn. "The boys are ready."