MAE SAI, Thailand — With more rain coming, Thai rescuers are racing to pump out water from a flooded cave before they can extract 12 boys and their soccer coach with minimum risk, officials said Thursday.

A firefighter who has been working on draining the water said parts of a passage leading to the chamber where the group was found Monday was still flooded to its ceiling, making diving the only way out.

"What we worry most is the weather," Chiang Rai provincial Gov. Narongsak Osatanakorn told reporters. "We can't risk having the flood back into the cave."

The boys, aged 11-16, and their 25-year-old coach went exploring in the Tham Luang Nang Non cave in the northern province after a soccer game June 23. Monsoon flooding cut off their escape and prevented rescuers from finding them for 10 days.

The boys, although skinny, have been described as in good health. Authorities have said the soccer players are being looked after by Thai navy SEALs, including medics, staying with them inside the cave.

Narongsak said he asked the SEALs in charge of extraction plans to estimate what sort of a risk would be involved to take them out and "what kind of readiness we can have today and decide if we can take that chance." He said the 13 may not be extracted at the same time, depending on their condition. They've practiced wearing diving masks and breathing, in preparation for the possibility they may have to dive.

"This morning, I have asked for 13 sets of (diving) equipment to be prepared and checked the equipment lists and place them inside (the cave) in case we have to bring them out in this condition with less than 100 percent readiness," he said.