A former Thai military diver working to save a young football team trapped inside a flooded cave drowned Friday as officials warned the window of opportunity to free the 12 boys and their coach is "limited".  The divers death highlights the risks for trying to find a safe way to bring the boys and the coach out through cramped passageways deep inside the waterlogged Tham Luang cave. Thailands Navy SEAL commander indicated that rescuers may have little choice but to attempt the tricky extraction of the group in comments on Friday, in the first official admission that they cannot wait out the monsoon underground. "At first, we thought the children could stay for a long time... but now things have changed, we have a limited time," Apakorn Yookongkaew told reporters. A somber mood has clouded the elation from earlier in the week, when the boys were found disheveled and hungry but alive on a ledge kilometers inside the cave. The diver, identified as Saman Kunont, passed out and died while returning from the chamber where the boys are trapped. He was part of a team trying to establish an oxygen line to the chamber where the children are awaiting rescue. Chiang Rai deputy governor Passakorn Boonyaluck delivered the "sad news" of the divers death to reporters massed at the entrance to the cave complex. "On his way back he lost consciousness," Navy Seal commander Apakorn said, adding he died despite the desperate efforts to help bring him out. Asked how the boys could make it out safely if an experienced diver could not, Apakorn said they would take more precautions with the children. Many of the boys -- aged between 11 to 16 -- are unable to swim and none has diving experience. The boys and their 25-year-old coach went exploring in the cave after a soccer game June 23. Monsoon flooding cut off their escape and prevented rescuers from finding them for almost 10 days as the only way to reach them was by navigating a series of dark and tight passageways filled with muddy water and strong currents.