The four survivors rescued on Monday have all been hospitalized in Chiang Rai, the nearest large city, Mr. Narongsak said.

“All of them are safe and conscious,” he said.

Those rescues bring the total to eight, after two days of pulling team members from the cave. Twelve players of the Wild Boars soccer team and their coach were trapped in the flooded cave complex on June 23.

“2 days, 8 Boars,” said a message on the Thai Navy SEALS Facebook page.

Officials have declined to identify any of the people who have been rescued or those who remain in the cave.

One good sign for the next stage of the operation is that the pace of the rescue was considerably quicker on the second day. On Sunday, it took 11 hours to bring out four people. But on Monday, it took only nine hours to bring out the next four, he said.

He said that was in part because the divers had become more skilled in maneuvering through the cave’s flooded passageways while holding the boys below them. It also helped that more than 100 people participated in the operation, more than on the first day, he said.

Mr. Narongsak said he was optimistic about the chances of bringing out all of the remaining five on Tuesday.

“We think we will do it better and the success will be 100 percent,” he said.

Officials said that a new weir, or low dam, built outside the cave was helping to keep water levels relatively stable within. The weather was cooperating, too: After a day of torrential downpours on Sunday, things cleared up on Monday.