Cave divers are squeezing through narrow, flooded corridors in a delicate operation to reach seven villagers trapped underground in a cave in Laos for nearly a week.

The villagers went into the cave in the central Laotian province of Xaisomboun last Wednesday in search of gold, but heavy rain triggered flash flooding which blocked the exit, the Associated Press reported, citing Laos and Thai rescue teams.

Two Thai and a Finnish divers who helped in the 2018 dramatic cave rescue of a young soccer team in Thailand arrived at the site Monday to join the effort to free the trapped villagers, state-run Laophattana News reported.

To reach the trapped villagers, rescuers will have to navigate a 340-meter (1,115 feet) tunnel, according to MTK Command and Control Center, one of the groups coordinating the rescue.

For most of the way, they’ll have to crawl to reach the villagers, as the narrowest point of the tunnel measures just 60 centimeters (23 inches), the group said.