MAE SAI, Thailand (AP) — Thai authorities said the second phase of the operation to rescue a youth soccer team trapped in a flooded cave was underway Monday, a day after four boys were pulled from the complex after more than two weeks underground.

Chiang Rai acting Gov. Narongsak Osatanakorn said the second phase began at 11 a.m. and authorities "hope to hear good news in the next few hours." Nine people remain trapped in the cave.

Authorities have been rushing to extract the boys, ages 11-16, and their coach from the cave as monsoon rains bore down on the mountainous region in far northern Chiang Rai province. Authorities said heavy downpours overnight did not raise water levels in the cave, where workers continue to pump water out.

The four boys pulled from the cave Sunday in an urgent and dangerous operation that involved them diving through the cave's tight and twisting passages were in good health. Still, they were undergoing medical checks in a hospital and were not yet allowed close contact with relatives due to fear of infections, who were able to see them through a glass partition.

Interior Minister Anupong Paojinda had said early Monday that the same divers who took part in Sunday's rescue would return to extricate the others as they know the cave conditions and what to do. He had said fresh air tanks needed to be laid along the underwater route.