Volunteers carelessly pump water back into the cave where the Thai soccer team is trapped.

Narongsak Osotthanakorn, the leader of the rescue operation to rescue the boys trapped in Tham Luang cave in Chiang Rai province, said yesterday that some unregistered volunteers had pumped water into the ground, causing it to flow back into the flooded cave, according toBangkok Post.

"They probably believe their technique is effective for underground drainage, but anything that is not in the plan must be discussed with us first. We are worried about rain and have to fight against floodwaters, but water is flowing back into the cave even though we have blocked the passages," Narongsak said.

He added that pumping water from the Tham Luang cave was the main activity in the operation. Authorities had deployed hundreds of pumps and installed power lines to assist the rescue work.As of yesterday morning, pumps had helped lower the water level in the cave by more than a centimeter per hour, but some passages were still completely flooded.

The telephone line to the boys' location has not been restored, causing rescue supervisors to worry about delays in getting updates from the boys. It takes divers six to seven hours to travel between the boys' location and the command center in the third chamber, where rescuers can call supervisors who will make decisions about the rescue operation.

Another important task is to find an entrance from the ground that leads directly down to the boys. If found, rescuers can drill a hole to create a way out instead of having the boys learn to dive. About 30 rescue teams are scouring the area above the cave.

Mr Narongsak said rescuers were estimating how much time they had before they would be forced to get the boys out, in case heavy rains caused floodwaters to rise, endangering both the team and rescuers.