MAE SAI, Thailand — Relief has given way to anxiety around the site of a vast cave complex where a soccer team of 12 boys and their 25-year-old coach remain trapped after 11 days, as rescuers deliberate the best way to extract them before severe storms hit.

The boys were being given rudimentary diving lessons Wednesday, even though none of them knows how to swim. Water levels have receded, but volunteer divers who have spent hours deep in the cave complex say currents remain strong, and even they have to hold on to ropes to haul themselves out. 

“The water is still too rough for the boys now,” said Tiraya Jaikaew, who leads a team of volunteer rescue divers helping the Thai navy. “We are focusing on setting up ropes in each section of the cave to help them.”

Videos released Wednesday by the Thai navy, which is overseeing the effort, show the boys in apparently good spirits, introducing themselves to the camera, with their palms pressed together in the traditional greeting.

Another video shows a Thai doctor, who spent the night with them in the cave, treating their cuts and bruises and joking with the boys, many of whom appear to have new clothes and were wrapped in heat-retaining foil blankets.

The 11-day drama has riveted the country and much of the outside world after the young soccer players, ranging in age from 11 to 16, disappeared while exploring the vast Tham Luang cave complex and then were trapped by rising floodwaters.

Divers finally found them huddled on a patch of dry ledge in one chamber, but getting them out remains a problem. The 2.5-mile journey through winding, flooded passages would normally be navigable by only the most experienced divers.

The scene in Thailand during a rescue operation to save boys trapped in a cave

The boys and their soccer coach are seen as they were found in a partially flooded cave, in Mae Sai, Chiang Rai. (AP)

Thai authorities are also hoping to remove enough water so that the boys could perhaps escape by foot, with their heads right above the water level. After pumping out about 30 million gallons, authorities have reduced water levels by 30 to 40 percent, they said Wednesday. Unseasonably dry weather has helped, but it is not predicted to last.

If the boys can be trained up and the water sufficiently reduced, an extraction could happen within days, they added.

At the rescue site Wednesday afternoon, Thai soldiers conducted their first evacuation drill — locking arms as they formed a column from the cave’s entrance to a field, where 13 ambulances were waiting to take the group to a hospital.

The drill simulated what a rescue would look like and how the boys would be transported to the hospital when they are eventually freed from the cave. It also raised hope among family members, some of whom have stayed at the chaotic, muddy site where rescue operations have been coordinated since the boys disappeared. An aunt of one of the boys, who declined to be named because of strict controls around their interactions with the press, said authorities had told her a rescue could be staged as soon as Thursday.

More rain is predicted for the weekend, and Thailand’s monsoon season will stretch until September. If a rescue attempt is not made soon, it may be months before the boys and their coach see daylight. 

Thai authorities have emphasized that they will not endanger the boys’ lives during the extraction and will attempt the rescue only when it is “100 percent safe.”

“The water is very strong, and space is narrow. Extracting the children takes a lot of people,” Deputy Prime Minister Prawit Wongsuwan told reporters, according to the Reuters news agency. “Now we are teaching the children to swim and dive.”

After days of solitude, the boys are receiving a string of visitors, including rescue divers and health professionals, and they are being fed liquid high-protein food.

Divers are also attempting to string a fiber-optic cable through the caves to give them phone contact with the outside world and their families. Even that has been a fraught process. The cable had not yet gotten within 50 yards of the boys, the range in which it can provide a service akin to a home wireless connection. An official from CAT Telecom, a state-owned company that runs Thailand’s telecommunications infrastructure, said rescuers would have to dive another four hours to get the cable close enough.  

The boys were first found by a pair of British divers, who described a harrowing three-hour round trip through narrow passageways flooded with water while trying to fight a strong current — indicating the magnitude of the challenge of bringing the boys out along the same route.

Their plight attracted the attention of one of the 33 Chilean miners who were trapped for 69 days nearly a half-mile below the surface in 2010. They got out only after engineers drilled down to their chamber.  

“They shouldn’t be ashamed to be scared,” Omar Reygadas, one of those miners, told the Associated Press. He ascribed his comrades’ survival to faith, prayer and humor. “Because we were scared, too. Our tears also ran. Even as adult men, we cried,” he said.

The complexity of the Thai cave, with its honeycomb of chambers and passageways, however, makes drilling a hole as an escape route an unlikely option.

By Wednesday, thousands of journalists had descended on the quiet town of Mae Sai, in the northern province of Chiang Rai, close to Thailand’s border with Myanmar. At the rescue site near the cave complex, vehicles ranging from SUVs to motorcycles zigzagged in and out along the muddy terrain, as vendors set up noodle stalls and massage booths for the volunteers.

For volunteer divers like Tiraya, joining the navy personnel and other rescuers was simply a calling. Tiraya, who runs a computer repair shop, has temporarily closed his day business in Lampang, about 140 miles south, and moved to the site to help coordinate the navy’s rescue efforts. 

“I have spent 10 years as a rescuer, but nothing has ever been like this,” he said. “I’ve never seen an effort as big as this in my life. It is really special.” 

Jittrapon Kaicome in Chiang Mai contributed to this report.