Tham Luang caves, Thailand (CNN)The perilous mission to evacuate 12 boys and their 25-year-old coach trapped deep inside a flooded cave in northern Thailand is under way, Thai authorities announced Sunday.
“Our readiness is at the highest today. Today is D-day,” said Chiang Rai’s governor, Narongsak Osotthanakorn, adding that the families had been informed of the plan and given their support to the rescue effort. At 10 a.m. local time, an international contingent of 13 specialist divers and five Thai Navy Seals descended into the watery network of underground tunnels below the Mae Sai mountains, carrying with them the hopes of an entire nation.The plight of the stricken boys, who have remained trapped inside the caves for 15 days, has transfixed Thailand, as rescue efforts have become ever more urgent. Rescuers have what has been described as a dwindling window of opportunity, with forecasters predicting the return of heavy monsoon rains in the coming days, effectively sealing off the cave until October.Read MoreRace against time At the site of the caves, volunteers assisting in the operation described the rescue attempt as a “now or never” scenario. The boys and their coach are huddled together in a small chamber 4 kilometers (2.5 miles) inside the cave, surrounded by flood water and with a limited supply of oxygen.To reach them, divers will need to successfully navigate a network of sprawling narrow tunnels, with officials close to the operation suggesting rescuers will use a “buddy” system, with each diver paired with a child. Extra oxygen tanks will also be positioned along the route.Signs that a rescue operation was under way were evident in the hours leading up to the announcement, as authorities installed a large green tarp around the cave entrance and removed media from outside of the camp to a separate location.On the dirt track leading to the tunnels, a near continuous convoy of trucks and military vehicles delivered troops and medical equipment, including a large cache of oxygen tanks. On Saturday evening, numerous international military advisers could be seen entering the site, followed later by four monks in orange robes.At the entrance to the site, a newly placed, thin white decorative flag fluttered in the wind, a Buddhist sign to indicate positive energy. Photos: Thai soccer team trapped in caveThis image, taken from video on Monday, July 2, shows the youth soccer team that has been trapped in a Thai cave since June 23.Hide Caption 1 of 25 Photos: Thai soccer team trapped in caveDivers have been able to bring food, blankets and other supplies to the boys while experts debate how to get them out safely. The team was found around two kilometers (1.24 miles) into the cave and somewhere between 800 meters to one kilometer below the surface, according to a British Cave Rescue Council briefing note.Hide Caption 2 of 25 Photos: Thai soccer team trapped in caveThe team was found alive by British divers. The search has brought rescue teams from all over the world.Hide Caption 3 of 25 Photos: Thai soccer team trapped in caveA Thai military medic provides first aid to one of the boys.Hide Caption 4 of 25 Photos: Thai soccer team trapped in caveThe body of Saman Kunan, a former Thai Navy SEAL, is carried during a repatriation and religious rites ceremony on Friday, July 6. Kunan died at 2 a.m. Friday as he returned from an operation to deliver oxygen tanks to the cave. He ran out of air while underwater, an official said.Hide Caption 5 of 25 Photos: Thai soccer team trapped in caveThai police take a break for breakfast as rescue operations continue on Wednesday, July 4.Hide Caption 6 of 25 Photos: Thai soccer team trapped in caveWater is pumped out of the cave during rescue efforts on Tuesday, July 3.Hide Caption 7 of 25 Photos: Thai soccer team trapped in caveWorkers fix the road leading to the cave on July 3.Hide Caption 8 of 25 Photos: Thai soccer team trapped in caveDivers prepare a light to be used for the underwater search on Monday, July 2.Hide Caption 9 of 25 Photos: Thai soccer team trapped in caveRescue workers wait at the entrance to the cave on July 2.Hide Caption 10 of 25 Photos: Thai soccer team trapped in caveSome of the team’s family members celebrate after receiving news that the team was alive.Hide Caption 11 of 25 Photos: Thai soccer team trapped in caveTechnicians lift water pumps to the drilling site on Sunday, July 1.Hide Caption 12 of 25 Photos: Thai soccer team trapped in caveSoldiers and rescuers work outside the cave complex on July 1.Hide Caption 13 of 25 Photos: Thai soccer team trapped in caveMonks attend a Buddhist prayer for the team on July 1.Hide Caption 14 of 25 Photos: Thai soccer team trapped in caveScuba tanks are delivered to the search site on July 1.Hide Caption 15 of 25 Photos: Thai soccer team trapped in caveRescue workers carry water-pumping equipment into the cave on July 1.Hide Caption 16 of 25 Photos: Thai soccer team trapped in caveA Thai Air Force worker drops near a possible cave opening on Saturday, June 30.Hide Caption 17 of 25 Photos: Thai soccer team trapped in caveBritish cave diver Robert Charles Harper explores an opening on Friday, June 29.Hide Caption 18 of 25 Photos: Thai soccer team trapped in caveRelatives of the trapped team members pray on Wednesday, June 27.Hide Caption 19 of 25 Photos: Thai soccer team trapped in caveFamily members waited more than a week for news of their loved ones.Hide Caption 20 of 25 Photos: Thai soccer team trapped in caveThai soldiers bring hoses and additional water pumps as the search for the team continued on June 27.Hide Caption 21 of 25 Photos: Thai soccer team trapped in caveVolunteer paramedics wait near the cave entrance on June 27.Hide Caption 22 of 25 Photos: Thai soccer team trapped in caveA rescuer looks for a cave entrance on June 27.Hide Caption 23 of 25 Photos: Thai soccer team trapped in caveRescuers search the cave on Tuesday, June 26.Hide Caption 24 of 25 Photos: Thai soccer team trapped in caveThai soldiers relay cable at the search site on June 26.Hide Caption 25 of 25High riskHopes had been high that an alternative means of rescue would be discovered. For days, specialist teams have scoured mountains above the cave in search of a possible hidden entry point.Divers have previously described conditions in the cave network as some of the most extreme they have ever faced.The decision to remove the boys using divers would not have been taken lightly. On Friday, a former Thai Navy SEAL died while returning from an operation to deliver oxygen tanks to the cave where the boys are located.Even if the divers are successful, it will be many hours before the fate of the boys and their rescuers will be known, with Thai authorities suggesting the extraction process could take days. It has previously taken divers 11 hours to complete the round trip.Men from the Department of Disaster Prevention and Mitigation arrive to the cave entrance on July 6, in Chiang Rai, Thailand. Finnish volunteer diver Mikko Paasi, a long-term resident of Thailand, said the death of the Thai Navy SEAL had changed the mood on the ground and made real for rescuers just how dangerous the mission had become.”Definitely, you can feel it that it has an effect, but we’re moving on. Everyone is a professional so we’re trying to put it away and avoid it happening again,” he said, adding: “Everybody is focusing on getting these boys out — keeping them alive or getting them out.”Spirits highIn the hours preceding the rescue, a letter the boys had sent to their families was published on the Thai SEALs’ Facebook page. The letter shows the boys in good spirits despite their ordeal.In neat blue handwriting, 11-year-old Chanin Viboonrungruang, the youngest of the group, told his parents not to worry, and said he was looking forward to eating fried chicken. His parents, who along with other families, have maintained a constant vigil at the site since the boys first became trapped.Chanin Viboonrungruang, 11, is in his final year of Anubanmaesai primary school in Mae Sai.On reading the letter Saturday evening, Chanin’s father, Tanawut Viboonrungruang, said he felt a great sense of relief. “I had been worried about my son, that he would be exhausted, he would be tired,” he said. For families the wait for news of their boys’ rescue has been excruciating.”I was worried about him as there are obstacles to extract him out. Everyone knows that it is difficult to stay inside (the cave) but the officials are trying (to help him),” said Viboonrungruang.”I hope he is still healthy and would come out soon. I want to send my support to him. I don’t have a chance to talk with him,” he said.