Thai authorities are stepping up their search for a team of young footballers missing in a cave.
Specialists aim to pump out water to allow navy divers to operate in the Tham Luang Nang Non cave complex, a Thai minister said.
The 12 boys aged 11 to 15 and their 25-year-old coach disappeared late on Saturday afternoon after apparently entering the cave, in Chiang Rai province in Thailand’s north.
Interior minister Anupong Paojinda said divers could proceed only when enough water had been pumped out, so there was breathing space between the water and the ceiling.
He said rescuers were working night and day.
“I want to confirm to the media that the SEAL team will be working non-stop because it’s already dark here too,” he said.
“So night and day doesn’t make a big difference. They’ll just need to rotate.”
Authorities are using helicopters to explore the possibility there may be holes in the ceiling of the cave.
The group became trapped when a heavy rainstorm flooded a stream at the cave’s entrance.
Police chief Komsan Saardluan said parts of the cave, which is estimated to be four to five miles long, get flooded to a height of up to 5m (16.5ft) during the rainy season, which runs from June to October.
Television showed footage of bikes and backpacks left at the cave entrance.
The search began at about midnight on Saturday after police received a report of a missing child from a mother.
Rain that has fallen overnight has increased the difficulty of exploring inside the cave.
The members of the team, the Wild Boars, have been known to cycle mountain roads and swim in waterfalls together when they are not playing football together.
Officials said tourists trapped in the cave in the past by floods have been rescued after the waters receded and it wasn’t the first time some of the boys had been inside the cave.