The operation to rescue a group of boys and their football coach from a flooded cave in Thailand could resume on Monday.
Four boys were brought to the surface on Sunday, more than two weeks after the group were trapped underground.
The Thai official leading the rescue operation, which has involved British divers, said it has gone “better than expected” and that the healthiest boys have been taken out first.
Authorities said the next phase could begin at any time during a 10-hour window that began at around 7am (1am BST) on Monday.
Heavy rain hit the area on Sunday night, with storms forecast throughout the week for the northern Chiang Rai province.
Meteorologists estimated a 60% chance of rain in the area on Monday.
It was not immediately known how rainfall had impacted water levels inside the caves where an international rescue effort is being staged.
On Sunday, chief of operations governor Narongsak Osatanakorn said 13 foreign and five Thai divers are taking part in the operation.
The British Cave Rescue Council (BCRC) confirmed that seven divers from the UK with “expertise in cave diving” are assisting.
Two elite British divers, Rick Stanton and John Volanthen, were the first rescuers to reach the group on Monday night and are believed to be part of the team.
A BCRC spokesman said: “The UK divers are part of the core team, so they will be actively involved and that will include escorting each child out through the flooded passage.
“The operation is being supervised by the Thai authorities.
“They have had to make a quick decision because they are really concerned about the water level rising.”
Two divers were expected to accompany each boy as they are gradually extracted.
The entire operation to get all 13 out of the cave could take two to four days, depending on weather and water conditions, said Thai army Major General Chalongchai Chaiyakam.
A doctor and paramedics were standing by to provide medical attention whenever the rescue team emerges.
Rescuers have pumped millions of litres of water out of the cave network to try to extract the group through nearly a mile of tunnels.
Thai officials are not only racing against worsening weather, but also lowered oxygen levels in the underground complex.
Former Thai navy Seal Saman Kunan passed out making the dive on Friday and died.
The boys, aged 11-16, and their coach, 25, were trapped inside the Tham Luang Nang Non cave in the northern province of Chiang Rai after a football game on June 23.
Monsoon flooding cut off their escape and they have been on a rocky shelf inside a cave chamber since.
Although weak, they are largely in good health, authorities have said.
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