The source noted that the footballers were in the care of Navy Seals and receiving nourishment, but they were not yet receiving medical attention.
It is expected that the 13 will undergo scuba training on Wednesday with the Seals and experts from Britain and the US.
They will also need to undergo a medical examination and it’s likely to be at least two days before they are strong enough to be evacuated.
Chinese divers have been assigned to build a pulley system to facilitate the movement of gear and other necessities into the cave.
With the Meteorological Department forecasting heavy rain in Chiang Rai on Wednesday and Thursday, the source said, a contingency plan is ready in case the water level rises again.
Food and drinking water is being stocked up, sufficient for three or four more days.
As of Wednesday morning, 70 oxygen tanks had been transported to the location where the footballers were stranded, beyond the area known as “Pattaya Beach”. Another 30 tanks are to be taken in, the source added.