Lao and Thai rescue teams prepare their equipment during the ongoing rescue mission in Xaysomboun province to locate two missing men.    --Photo Manat K Artmongkron

Knocking sounds raise hope in cave rescue operation

Rescuers are racing against time to reach two men missing in a flooded cave in Xaysomboun province after detecting sounds that may signal they are still alive.
The Thai chief rescuer, Mr Kengkaj Bongkawong, said rescue teams recently discovered a key vertical shaft after following contour lines identified through satellite scans and specialised mapping software.
The shaft is believed to be close to chambers four and five of the cave system, where the two missing men are thought to be sheltering.
Mr Kengkaj said in a post on Facebook that rescue teams had spent days climbing mountains above the cave, scanning the terrain, and tapping cave walls every five metres in a determined effort to locate the missing pair.
The breakthrough came when a rappelling rescue team descended into the shaft and began knocking on the cave walls. Rescuers reported hearing sounds resembling rocks scraping in response.
The sounds were heard from below and did not appear to be echoes, raising hopes that the trapped men may have responded to signals.
“Yesterday, when knocks were sent down, there were response signals in the form of sounds resembling rock scraping, but today the signals had the character of knock responses — which have been preliminarily assessed as not being reflections or echoes of any kind,” he said.
However, he didn’t confirm whether the sound was from the two missing villagers.
The operation was temporarily suspended on Sunday because of heavy rain but resumed on Monday morning as teams pushed ahead with the search.
The latest development has provided a major boost to rescue workers and families anxiously awaiting news of the missing pair.
The rescue mission has already succeeded in bringing five men safely out of the cave.
The Thai cave-diving specialist, Mr Noraset Palasingh, known as Teacher Ben, said information gathered from the five survivors has strengthened confidence that the remaining two could still be alive.
“Yesterday I went and talked with all five survivors and learned a lot we didn’t know before. There are dry areas inside where they could be, and there’s still a chance they’re alive — so we’re not stopping the search,” he told the Lao media.
Mr Noraset said the survivors revealed the existence of dry chambers deeper inside the cave, where the missing men may have taken refuge. He said the two men may also have access to food and drinking water.
“The people further in had some food with them, though we don’t know how much. As for water, the survivors said they drank water from inside the cave — they filtered it and let the sediment settle, which is drinkable enough to sustain life for up to 10 days. We believe they’re still waiting for us to come and that they’re still alive,” he said.
Mr Noraset also described the difficult conditions facing rescuers. He said the cave is very different from Thailand’s Tham Luang cave, where an international rescue operation saved a youth football team in 2018.
“Very different. Tham Luang is a large cave — this one is much smaller. Tham Luang had many branching passages, this one has only one way in but it’s extremely narrow. The hardest part is getting in and out — it takes a long time and the space is very tight,” he said.
The cave diver said the narrow flooded passages require patience and precision.
Following the rescue of the five other men, they publicly acknowledged that they entered the cave while searching for gold and thanked the rescue teams, volunteers and communities that helped save their lives.
The ordeal began on May 20, when seven men entered an uncharted cave in Xaysomboun province before heavy rainfall triggered a flash flood that blocked the exit.

By Phonepaseuth Volakhoun
 (Latest Update May 2, 2026)