Heavy rains are hampering efforts to reach 12 teenagers and their football coach who have been trapped in a cave in Thailand for four days, wrote BBC.

Rising water levels caused by overnight rains frustrated hundreds of rescue workers as they worked to drain water from inside the cave.

Officials are now trying to find another opening into the cave, after the main entrance became inaccessible.

There has been no contact with the group since Saturday.

Search teams are also using a drone with thermal sensors to fly over caves in the area, though low clouds are making it impossible for them to fly far, according to BBC correspondent Jonathan Head who is at the scene.

On Tuesday, navy divers had reported seeing fresh footprints inside the cave complex, raising hopes for the group's safety.

The cave can flood up to 5m during the rainy season.