THAM LUANG CAVE, Thailand — Searchers trying to reach a dozen boys and their soccer coach in a flooded cave complex used huge pumps to reduce the water level, allowing divers to place guide ropes and air tanks along the route, officials said Sunday.

It was the first significant progress in several days in the massive effort to reach the boys, aged 11 to 16, and their coach, 25, who have been missing in the cave complex in northern Thailand for more than a week. Rising floodwaters in the cave had stalled the search-and-rescue operation for days.

Given how long the boys and their coach have been missing, the odds of finding them alive seemed to be growing thin. But the governor of Chiang Rai Province, Narongsak Osottanakorn, who is overseeing the search-and-rescue operation, expressed hope that Thai Navy SEAL divers could soon reach the cavern where the group is believed to be.

“We are very happy with the result,” he said Sunday. “The water level is reduced, and it makes it easier for the SEALs.”