THAM LUANG CAVE, Thailand — The Thai authorities said on Thursday that they believed members of a youth soccer team trapped in a flooding cave complex could have reached a large, dry cavern, and officials were considering drilling through the mountaintop to reach them.

With the search for the team growing ever more urgent and complex on its sixth day, Lt. Gen. Kraiboon Suadsong, commissioner of the Police Strategy Office, said a team would first try drilling a small hole through the rock above the cavern to allow a camera to be lowered in.

“We will drill and use an infrared camera that can take photos,” he said in an interview with The New York Times. “We know the spot where we should be drilling.”

General Kraiboon said crews had tripled the volume of water being pumped from the interior of the flooded cave system, which could help make its submerged passageways accessible.