Thailand's soldiers were searching for alternative entrances into Tham Luang Nang Non cave on Friday, as the search for 12 children and their football coach entered its seventh day. The authorities have deployed specialized Navy diving teams to explore the partially flooded cave, with US and UK divers also joining the effort. The rescue operations, however, have been hampered by heavy rain.

With the main entrance blocked by flooding, the government has been deploying water pumps and drilling makeshift drains to battle the rising water levels.

"The water level has receded but it's still too high to dive in," Chiang Rai Governor Narongsak Osotthanakorn told reporters Friday. 

At the same time, the authorities deployed drones to aid soldiers looking for spots to create another entrance into the sprawling cave.

"It's possible in theory but could be hard because the [drill] machine weighs 2 tons, so we have to figure out how to lift it and where to place it," Narongsak said.

Read more: Navy divers search for children trapped in Thai cave

A note in the emergency box

Rescuers also lowered 20 boxes with food, water, medicine, and flashlights down a fissure leading to the cave on Friday, in the hope that the boys would find them. Each box also contains a map and a note that says "if you receive this, please mark on the map where you are. Everyone will come and help you immediately."

"If the children find this box we want them to float the box out of the cave," Police Colonel Kraiboon Sotsong told reporters.

The children, aged 11 to 16, train for a local football team and are believed to be somewhat familiar with the cave.

Their parents have been camping out the Tham Luang Nang Non cave since the children's bicycles and the coach's motorbike were found at the entrance last week.

dj/msh (dpa, AFP, Reuters)