Thai rescue workers will drill a narrow shaft into a cave where 12 schoolboys and their soccer coach are believed to be trapped by flood waters on the fourth day of a search that has been hampered by heavy rain.
The boys, aged between 11 and 16, and their 25-year-old assistant coach, went missing on Saturday after soccer practice when they set out to explore the Tham Luang cave complex.
The complex is known to be prone to flooding in the rainy season.
Thai volunteers and military teams, including 45 navy SEAL unit members, have been deployed at the flooded cave complex, which runs 10km under a mountain in the northern province of Chiang Rai.
While distraught relatives and friends gathered at the mouthof the cave, rescue workers pumped water out, but the persistent heavy rain has slowed their progress.
According to messages the boys exchanged before setting off, they had taken flashlights and some food.
Apart from some footprints and marks left by their muddy hands near the cave entrance, nothing has been seen or heard of them since Saturday evening, and the race to find them has dominated Thai news cycles.
"I'm confident all are still alive," Prime Minister Prayuth Chan-ocha told reporters.
Vern Unsworth, a British cave explorer based in Chiang Rai who has joined the search, said a lot of water was seeping into the cave from two directions.
"There is a watershed inside, which is unusual, it means there is water coming in from two directions," he said.
"The biggest challenge is the water. Massive amounts."
Thai Navy SEAL said on their Facebook page that water levels rose 15cm overnight and that a third chamber of the complex cave network, believed to be several kilometres long, was now flooded.
Soldiers carried large hoses into the cave today to continue draining rising flood waters.
Distraught relatives have been camped out for days praying for the team's safe return.
Three foreign divers coming from Britain were expected to reach Thailand this evening to join the search, the country’s interior minister said.
Thailand has also asked the United States for survivor detection equipment.
The head coach of the soccer team, who did not attend practice on Saturday, said the boys had visited the caves several times, and was hopeful that the boys would stick together and stay strong.
"They won't abandon each other," he told reporters.
