British cave-diver Robert Charles Harper explores an opening in the mountain during rescue operation for a missing children's football team and their coach in Tham Luang cave, Chiang Rai province on June 29, 2018 - A newly-discovered opening to a flooded Thai cave where 12 children and their football coach have been stuck for six days raised hopes for the massive rescue operation for survivors on June 29. (Photo by Krit PHROMSAKLA NA SAKOLNAKORN / THAI NEWS PIX / AFP)        (Photo credit should read KRIT PHROMSAKLA NA SAKOLNAKORN/AFP/Getty Images)
PHOTO: Krit Phromsakla Na Sakolnakorn/AFP/Getty Images
British cave-diver Robert Charles Harper explores an opening in the mountain during rescue operation for a missing children's football team and their coach in Tham Luang cave, Chiang Rai province on June 29, 2018 - A newly-discovered opening to a flooded Thai cave where 12 children and their football coach have been stuck for six days raised hopes for the massive rescue operation for survivors on June 29. (Photo by Krit PHROMSAKLA NA SAKOLNAKORN / THAI NEWS PIX / AFP) (Photo credit should read KRIT PHROMSAKLA NA SAKOLNAKORN/AFP/Getty Images)
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CHIANG RAI, THAILAND - JULY 18:  Twelve boys and their coach from the "Wild Boars" soccer team arrive for a press conference for the first time since they were rescued from a cave in northern Thailand last week, on July 18, 2018 in Chiang Rai, Thailand. The 12 boys, aged 11 to 16, and their 25-year-old coach were discharged early from Chiang Rai Prachanukroh hospital after a speedy recovery and thanked those involved in their rescue. (Photo by Linh Pham/Getty Images)
PHOTO: Linh Pham/Getty Images
CHIANG RAI, THAILAND - JULY 18: Twelve boys and their coach from the "Wild Boars" soccer team arrive for a press conference for the first time since they were rescued from a cave in northern Thailand last week, on July 18, 2018 in Chiang Rai, Thailand. The 12 boys, aged 11 to 16, and their 25-year-old coach were discharged early from Chiang Rai Prachanukroh hospital after a speedy recovery and thanked those involved in their rescue. (Photo by Linh Pham/Getty Images)
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An ambulance leaves the Tham Luang cave area after divers evacuated some of the 12 boys and their coach trapped at the cave in Khun Nam Nang Non Forest Park in the Mae Sai district of Chiang Rai province on July 8, 2018. - Elite divers on July 8 began the extremely dangerous operation to extract 12 boys and their football coach who have been trapped in a flooded cave complex in northern Thailand for more than two weeks, as looming monsoon rains threatened the rescue effort. (Photo by LILLIAN SUWANRUMPHA / AFP) /         (Photo credit should read LILLIAN SUWANRUMPHA/AFP/Getty Images)
PHOTO: LILLIAN SUWANRUMPHA/AFP/Getty Images
An ambulance leaves the Tham Luang cave area after divers evacuated some of the 12 boys and their coach trapped at the cave in Khun Nam Nang Non Forest Park in the Mae Sai district of Chiang Rai province on July 8, 2018. - Elite divers on July 8 began the extremely dangerous operation to extract 12 boys and their football coach who have been trapped in a flooded cave complex in northern Thailand for more than two weeks, as looming monsoon rains threatened the rescue effort. (Photo by LILLIAN SUWANRUMPHA / AFP) / (Photo credit should read LILLIAN SUWANRUMPHA/AFP/Getty Images)
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(CNN) —  

A medical assessment of the 12 boys and their football coach stuck in a cave in Northern Thailand concluded that it was too dangerous to try to move the group out Thursday, according to a member of the Thai Navy SEALs who is not authorized to speak to the media.

The SEALs have started to pump oxygen into the chamber.

Separately, a new doctor’s report highlighted that two of the boys and the coach were suffering with exhaustion from malnutrition.

Fresh details of the operation underway at the Tham Luang Nang Non to free the team were emerging, as rescuers pushed ahead with multiple plans to extricate the group trapped underground for almost two weeks.

More rain is forecast this weekend, putting pressure on rescuers to formulate a plan to extract the boys before flood waters rise any higher.

Huge volumes of water are being pumped out of the cave complex each day, but the narrow, winding passages inside are still flooded, meaning diving through the murky water is currently the only way in and out.

Rescuers entering the cave complex located in northern Thailand have to navigate dark, flooded tunnels for six hours to reach the team. It takes another five hours to return to the entrance.

An additional 30 SEALs arrived on site to reinforce rescue operations, according to Captain Supachai Thanasarnsakorn, deputy chief of the Thai Navy SEALs. They join the 80 already involved in the rescue operation comprising active, reserve and former SEALs.

Around the camp which has sprung up near the cave entrance, Thai military divers have set up an encampment with diving gear and equipment, while people from the local community hand out food to rescuers, other volunteers and the small army of press on site.

Related: Why will it take so long to rescue the trapped Thai soccer team?

Trying to stop the water

The boys were in good spirits despite spending almost two weeks underground, Chiang Rai governor Narongsak Osottanakorn said.

“I confirm here again that they are in good health and they are smiling and playing around,” he said.

International rescue effort

Australia -- Australian police divers are taking part in rescue efforts and helping with planning.

China -- Six rescue specialists from NGO Beijing Peaceland Foundation are assisting Thai divers.

Israel -- Israel's Maxtech Networks is providing radio and communication equipment.

Laos and Myanmar -- Thailand's neighboring countries each sent rescue workers and divers.

UK -- Two UK divers were first to discover the boys, earning one a commendation from the British Cave Rescue Council.

US -- US Indo-Pacific Command (PACOM) sent 30 military personnel, including divers.

The last images the world saw of the boys was on Wednesday in a video where they introduced themselves one-by-one, saying “I am healthy.”

Since they were found late Monday local time by a duo of British expert cave divers, Thai Navy SEALs have stayed with the team, tending minor wounds and giving them food to build up their strength.

The boys remain weak after spending days in the darkness, barely moving from the small, muddy ledge, away from the water.

While rescuers are trying to pump enough water out of the cave to allow the boys to simply walk out, Thai Navy SEALs are also teaching them how to scuba dive.

The boys would need to wear full-face diving masks to enter the narrow tunnels in moving water, though many experts say this would be a dangerous option for novice divers.

In an attempt to maintain the boys’ morale, rescue teams have prioritized installing a line of communication between the boys and their parents.

However, they were still attempting to connect them Thursday after earlier efforts failed when the line became damaged after falling into water. CNN saw an old-style military phone and loops of cable being carried into the cave by engineers.

02:05 - Source: CNN
Thai cave rescue: 'I told them, don't lose hope.'
CHIANG RAI, THAILAND - JULY 18:  Twelve boys and their coach from the "Wild Boars" soccer team arrive for a press conference for the first time since they were rescued from a cave in northern Thailand last week, on July 18, 2018 in Chiang Rai, Thailand. The 12 boys, aged 11 to 16, and their 25-year-old coach were discharged early from Chiang Rai Prachanukroh hospital after a speedy recovery and thanked those involved in their rescue. (Photo by Linh Pham/Getty Images)
PHOTO: Linh Pham/Getty Images
CHIANG RAI, THAILAND - JULY 18: Twelve boys and their coach from the "Wild Boars" soccer team arrive for a press conference for the first time since they were rescued from a cave in northern Thailand last week, on July 18, 2018 in Chiang Rai, Thailand. The 12 boys, aged 11 to 16, and their 25-year-old coach were discharged early from Chiang Rai Prachanukroh hospital after a speedy recovery and thanked those involved in their rescue. (Photo by Linh Pham/Getty Images)
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PHOTO: LILLIAN SUWANRUMPHA/AFP/Getty Images
An ambulance leaves the Tham Luang cave area after divers evacuated some of the 12 boys and their coach trapped at the cave in Khun Nam Nang Non Forest Park in the Mae Sai district of Chiang Rai province on July 8, 2018. - Elite divers on July 8 began the extremely dangerous operation to extract 12 boys and their football coach who have been trapped in a flooded cave complex in northern Thailand for more than two weeks, as looming monsoon rains threatened the rescue effort. (Photo by LILLIAN SUWANRUMPHA / AFP) / (Photo credit should read LILLIAN SUWANRUMPHA/AFP/Getty Images)
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CHIANG RAI, THAILAND - JULY 01:  Rescue workers carry heavy water pumping equipments into Tham Luang Nang Non cave on July 1, 2018 in Chiang Rai, Thailand. Rescuers in northern Thailand looked for alternative ways into a flooded cave as they continued the search for 12 boys and their soccer coach who have been missing in Tham Luang Nang Non cave since Saturday night after monsoon rains blocked the main entrance. U.S. Forces and British divers joined the search as they worked their way through submerged passageways in the sprawling underground caverns as the search intensifies for the young soccer team, aged between 11 to 16, and their their 25-year-old coach.  (Photo by Linh Pham/Getty Images)
PHOTO: Linh Pham/Getty Images
CHIANG RAI, THAILAND - JULY 01: Rescue workers carry heavy water pumping equipments into Tham Luang Nang Non cave on July 1, 2018 in Chiang Rai, Thailand. Rescuers in northern Thailand looked for alternative ways into a flooded cave as they continued the search for 12 boys and their soccer coach who have been missing in Tham Luang Nang Non cave since Saturday night after monsoon rains blocked the main entrance. U.S. Forces and British divers joined the search as they worked their way through submerged passageways in the sprawling underground caverns as the search intensifies for the young soccer team, aged between 11 to 16, and their their 25-year-old coach. (Photo by Linh Pham/Getty Images)
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CHIANG RAI, THAILAND - JULY 18:  Twelve boys and their coach from the "Wild Boars" soccer team arrive for a press conference for the first time since they were rescued from a cave in northern Thailand last week, on July 18, 2018 in Chiang Rai, Thailand. The 12 boys, aged 11 to 16, and their 25-year-old coach were discharged early from Chiang Rai Prachanukroh hospital after a speedy recovery and thanked those involved in their rescue. (Photo by Linh Pham/Getty Images)
PHOTO: Linh Pham/Getty Images
CHIANG RAI, THAILAND - JULY 18: Twelve boys and their coach from the "Wild Boars" soccer team arrive for a press conference for the first time since they were rescued from a cave in northern Thailand last week, on July 18, 2018 in Chiang Rai, Thailand. The 12 boys, aged 11 to 16, and their 25-year-old coach were discharged early from Chiang Rai Prachanukroh hospital after a speedy recovery and thanked those involved in their rescue. (Photo by Linh Pham/Getty Images)
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