Eight of the 12 boys trapped in a flooded and labyrinth cave system in far northern Thailand are safe and recuperating in a hospital after another four were brought out by divers on the second day of a high-stakes rescue operation, a top official said.

The boys brought out of the dark, winding cave on Monday are “safe and conscious,” said Chiang Rai province acting Governor Narongsak Osatanakorn, who is in charge of the rescue effort. Prime Minister Prayuth Chan-ocha was visiting all eight in the nearby hospital that they were helicoptered to, he said.

Monday's operation began at 11am and took nine hours, two fewer than Sunday, with rescuers helped by the experience they've accumulated, Narongsak told a news conference punctuated with rounds of applause.

“We have more operating personnel. And we have more expertise than yesterday,” he said.

But rescuing the remaining five people, which includes the boys' 25-year-old soccer coach, could take more than one operation, Narongsak said.

The urgent and dangerous effort has involved the boys diving through the cave's tight and twisting passages, guided by experienced divers.

The Facebook page of the Thai Navy SEALs, who have been central to the rescue operation, was updated Monday night to say “two days, eight boars” a reference to the Wild Boars, the name of the boys' soccer team. The message, like most posted by the SEALs, ended with the fighting cheer adopted from the US Navy: Hooyah.

Authorities have been rushing to extract the boys, ages 11-16, and their coach from the cave as the annual monsoon bears down on the mountainous region in far northern Chiang Rai province. Workers have been laboring around the clock to pump water out of the cave, and authorities said Monday that heavy downpours overnight did not raise water levels inside.

Earlier Monday, Narongsak said the four rescued the day before were in good spirits.

“This morning they said they were hungry and wanted to eat khao pad grapao,” he said, referring to a Thai dish of meat fried with chili and basil and served over rice.

Still, the four were undergoing medical checks in a hospital in Chiang Rai city, the provincial capital, and were not yet allowed close contact with relatives due to fear of infections. Relatives were able to see them through a glass partition, Narongsak said.

The boys and their coach went exploring in the massive Tham Luang Nang Non cave on June 23 after a soccer practice, and were cut off when a rainstorm flooded the cave. A massive international search operation was launched and it took 10 days to locate the boys, who had taken shelter on a dry slope deep in the complex.

The search and rescue operation has riveted people both in Thailand and internationally, with journalists from across the globe traveling to this town along the border with Myanmar to report on the ordeal.

Authorities have said extracting the entire team from the cave could take up to four days, but two straight days of success raised hopes that it could be done faster.

Monday's mission involved 18 divers from Thailand and abroad.

Narongsak said rescuers would meet Monday evening to plan for the next operation. “We believe that we can do even better and it will be a 100 percent success,” he said.

“The divers that were assembled from many countries are proud to have conducted this operation until its success,” Narongsak said. “Some of them had gone to rest, some others are preparing for the next operation.” The perilous rescues have involved two divers accompanying each of the boys, all of whom have been learning to dive only since July 2, when searchers found them.

Cave rescue experts have said they consider an underwater escape to be a last resort, especially with people untrained in diving.

The death on Friday of a former Thai navy SEAL underscored the risks. The diver, the first fatality of the rescue effort, was working in a volunteer capacity and died on a mission to place air canisters along the passage to where the boys are, necessary for divers to safely travel the five- to six-hour route.

There were several concerns that prompted authorities to move forward with the plan to dive the boys out. One was that it was unknown how safe and dry the area where they had taken shelter would stay as Thailand's rainy season, which lasts until at least late October, picks up pace.

The other, and perhaps more worrying was that oxygen levels in the complex were falling close to dangerous levels.