BANGKOK — A search operation for seven villagers trapped inside a flooded cave in central Laos entered its seventh day on Tuesday, as rescuers encountered difficult terrain and weather as they are trying to reach the group whose condition remains unknown.

The villagers entered the cave in Xaisomboun province on May 19, but heavy rain triggered flash flooding that blocked the exit, according to Lao and Thai rescue teams involved in the operation.

The Lao organization Rescue Volunteer for People, which is working closely with the local authorities, posted on its Facebook page that Tuesday’s operation plan includes exploring air shafts above the cave in hopes of identifying possible access points. and locating the trapped people.

Rescuers from neighboring Thailand also arrived at the site over the weekend to assist the operation.

According to rescuers, divers have navigated about 100 meters into the flooded, narrow cave. They believe the villagers may be trapped about 30 meters beyond the furthest point currently accessible. They are working to pump water out of the cave to aid the search efforts.

The site is in a remote area in Xaisomboun province’s Longcheng district, which is about 120 kilometers (75 miles) north of the capital, Vientiane. Rescuers at the scene have detailed on social media the challenging mountainous terrain and heavy rain that is hampering the operation.

Videos shared online by Thai rescuers showed that reaching the cave’s entrance requires a steep hike on foot of roughly 4 kilometers (2.5 miles). The entrance is also steep and rocky, and barely wide enough for a single person to climb through at a time.

Inside, rescuers must go through muddy passageways, flooded sections and narrow tunnels that forced them to crawl forward.

There has been no official confirmation on why the villagers went into the cave, although the rescuers involved said that they went in to look for gold deposits.

Bounkham Luanglath of the Lao rescue group has told The Associated Press that the cave was frequented by local residents looking for gold, although authorities had repeatedly warned them against entering the cave out of safety concerns.

The average per capita income in Laos of about $2,000-2,500 is among the lowest in Southeast Asia, and it is less still in underdeveloped rural areas.

Laos is not known as a major gold producer, but its mining industry is sizable considering the country’s developing economy. The mining sector is fueled by foreign direct investment, largely from neighboring Thailand and China. Copper is a major export, and mining for rare earth elements, needed for most modern technologies, has become more common in Laos recently.

The Laos Foreign Ministry on Tuesday said it has no official information to share with the media. The Southeast Asian nation is a one-party communist state with no organized opposition and the government keeps a tight lid on information.

The news quickly drew headlines in Thailand because of its resemblance to the dramatic 2018 cave rescue in northern Thailand, where 12 boys and their soccer coach were trapped for more than two weeks before being safely rescued in an operation that became a global sensation. A former Thai navy SEAL diver was killed during the search and rescue effort.

A new tragedy occurred earlier this month, with five Italian divers found dead after they went missing while diving into a cave in the Maldives. A Maldivian military diver who was part of the recovery team was killed during the high-risk operation to retrieve their bodies.

A major health risk of being trapped in a cave is cold conditions quickly leading to hypothermia. The body can cope for weeks without food, but clean water is necessary to prevent dehydration. A contaminated water supply could cause diarrhea, hastening dehydration.

Declining oxygen levels cause symptoms similar to altitude sickness and in the long run can damage the lungs and other organs, while carbon dioxide buildup causes exhaustion and eventual unconsciousness.

Constant darkness disrupts time perception and the body’s circadian rhythms. It also causes extreme sensitivity when the eyes have to adjust again to light.

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Associated Press journalists Grant Peck, Anton L. Delgado and Haruka Nuga contributed to this report.