The painstaking mission to rescue 12 Thai boys and their football coach from a flooded cave complex has been paused for up to 20 hours as divers rest and replenish their supplies.

Four of the children have so far been rescued and taken to hospital, while others have undergone health assessments inside the cave.

Officials in Chiang Rai described Sunday as “D-Day”, with expert divers facing a race against time to free the group, who have been trapped for more than a fortnight, before monsoon rains return.

The children will need to be led through the Tham Luang cave, which consists of a series of narrow, waterlogged passageways, for around two-and-a-half miles in poor visibility.

Even the most experienced divers find the route challenging, and a former Thai Navy Seal died on Friday trying to make the journey.