The first of seven men who have been trapped in a flooded cave in Laos for more than a week has been brought to safety by divers, in a perilous rescue mission that has required teams to crawl through narrow, deluged tunnels, navigating sharp rocks and collapse hazards.

Four men remain inside a chamber about 300 metres (980ft) from the cave entrance, where they were found crouched and huddled together on a rocky ledge by rescuers on Wednesday. Two men are yet to be located.

“The first one is out. Safe and sound!!!” wrote Manat Artmongkron, a rescue technician for Saithan Saphanboon Foundation, a Thai rescue group, in a Facebook post.

Video posted on social media showed a man covered in mud clambering out of the cave to safety. He was met with some cheers and wrapped in an emergency blanket.

International diving teams, including some who worked on the dramatic rescue of a young Thai football team in 2018, have battled for days to retrieve the men. Reaching them required skilled divers to crawl and twist through incredibly narrow passageways, moving through muddy water with poor visibility.

Rescuers have been racing against time to pump water out from the cave, fearing that rains could soon begin again, further inundating the tunnels.

Josh Richards, an Australian cave diver who is part of the international team, described the conditions the team were battling against, including unstable clay and mud walls, which affected the water, meaning “you’re essentially diving in coffee. You’re not going to be seeing anything through it.”

As sections of the tunnel between the miners and the surface were completely flooded, the team on the ground was trying to pump out as much water as possible in a two-pronged approach, Richards said. The plan had been that if they were not able to pump the water out then they would use scuba equipment to rescue the men, he added.

Additional divers from Australia, Japan, France, Indonesia and Thailand were expected to arrive on Friday, while a Malaysian cave diver joined the efforts on Thursday.

Kengkard Bongkawong, the head of operations for Metta Tham Rescue, another Thai group, said on Facebook: “One person has been brought out of the cave safely. Four others remain, awaiting assessment. The search for the remaining two will continue tomorrow.”

Earlier, he warned that the search for the two missing men would be especially challenging, requiring teams to dive through a 25-metre-long narrow tunnel. “Diving in the narrow passage that has no space to make a U-turn, this is really dangerous so we need to evaluate the safety measures, principles, routes and expertise in the cave area,” he told local media.

Heavy machinery is being used to clear a route to the cave site so that equipment can be transported more easily. The cave is in a remote area of central Laos’s Xaysomboun province, and reaching it involves a 3-mile (5km) hike up mountainous terrain.

The group of seven men had been trapped inside the cave since last Wednesday, when they reportedly entered to search for gold ore and to hunt. Heavy rains inundated the cave, carrying in sand and gravel that blocked a crucial exit.