The effort to rescue the 12 boys and their soccer coach trapped in a Thailand cave is proving to be much more difficult than anyone expected.
Sgt. Saman Kunan died Friday morning from a lack of oxygen while attempting to return to a command center two kilometers (1.2 miles) inside the cave.
Kunan was delivering oxygen tanks to the part of the cavern where the boys have been stuck for two weeks when he ran out of air while underwater.
The rescue team will now install a "buddy dive" system for the boys, which involves each student being paired with a navy seal to personally guide them through each step of the 2.5 km long tunnel.
This kind of system allows divers to closely monitor their rescue partners and ensure safety while submerged.
Officials say oxygen levels are down to around 15%, so rescuers have been pumping air into the cave while attempting to pump water out.
The boys range from 11-16 years old, and it's reported that some of them can't swim.
Photo by Getty Images
Although things are getting increasingly dire, recent footage shows that the children for now are in good spirits:
Read more at BBC News.