Thai authorities say the second phase of an operation to rescue the remaining eight trapped boys and their soccer coach from a cave began at 11 a.m. (midnight ET).
A heavy but brief downpour hit the area Monday morning, but authorities said that did not change the water level in the cave, as workers continue to pump water out. New oxygen tanks were being placed before the second stage of the rescue effort began.
Four boys were retrieved from the cave Sunday. Chiang Rai provincial acting Gov. Narongsak Osatanakorn said the four healthiest boys were removed first.