Media playback is unsupported on your device Media caption The boys can be seen introducing themselves next to a diver in a wetsuit

A new video has been released of the 12 boys and their football coach trapped in a Thai cave, in which they say they are in good health.

Smiling and at times laughing, they introduce themselves one by one.

They were found on Monday after nine days trapped deep in the cave by rising water, and have since received food and medical treatment.

But their rescue may take months as they must either be taught to dive or wait for the water to recede.

The concern is that the rainy season has only just begun, so water levels in the Tham Luang cave will almost certainly continue to rise.

The video posted on the Thai Navy special forces Facebook page shows the team draped in foil blankets to keep them warm.

Image copyright AFP Image caption The boys all give their names, and a traditional Thai greeting

Lit by torches and with divers sitting alongside, they each give their name and the traditional "wai" greeting, putting their palms together.

Two other videos show the group having some light scratches treated by a military doctor. The boys are also again seen asking how soon food is coming.

Written on a rock in the cave can be seen the name of the football team and of the navy unit involved in the rescue.

Two Thai navy divers will be staying with the group underground from now on.

Could the group swim out?

"Now we are teaching the children to swim and dive," Thai Deputy Prime Minister Prawit Wongsuwan was quoted as saying by the Reuters news agency.

A report in The Guardian says the boys are being trained to breathe through scuba masks.

But a source inside the Thai navy diving team has told the BBC that taking the boys, few of whom can even swim, out through the narrow flooded passages is too risky.

He said the journey in to where they were, deep in the caves, had exhausted even experienced divers. So they were seriously considering keeping the boys there for the full four or five months of the rainy season, he added.

Some of the route involves squeezing through tight gaps underwater. In parts it is too narrow to wear an oxygen tank and the exits are not visible, so it would be easy for a child to panic.

However, other Thai officials say they may need to bring the boys out quickly if water levels rise. Weather forecasts for the area are being closely monitored for heavy rain which could trigger further flooding.

What are the trapped group having to endure?

Before they were found, they would have lived in total darkness once any torch batteries had expired.

However, the three basic conditions for survival were met:

The temperature in the cave is thought to be around 26C (79F) so hypothermia was not an issue

There was sufficient oxygen because air enters through porous limestone or cracks in the rocks.

They had drinkable water

Oxygen may yet become a problem should the water level rise and the air pocket they are in get smaller.

Unknown factors include the possibility of dangerous animals like snakes in the cave or of contamination from bat droppings.

What rescue efforts are being made?

Rescuers are trying to work out how best to bring them all to safety, with officials stressing they do not intend to take any risks with the boys' safety.

Media playback is unsupported on your device Media caption Families have been shown new footage of the 12 boys and their coach stuck in a cave in Thailand.

At a news conference, officials said no rescue attempt would be made on Wednesday but conditions were perfect for a rehearsal.

Water continues to be pumped out of the cave complex and officials have said they are confident they have been able to stop more water getting into the chamber the boys are in.

Emergency teams are also trying to install a phone line so the group can talk to their families but attempts to do so failed on Tuesday.

Outside the cave, medics are staging rehearsals in case the group can be brought out soon.

Other teams are still scouring the mountainside in the hope of finding another way into - and out of - the cave.

How did the group get trapped?

The boys, aged between 11 and 16, and their 25-year-old coach went missing on 23 June. It is believed they entered the cave in northern Chiang Rai province when it was dry and that sudden heavy rains blocked the exit.

It is thought they could at first move through parts of the cave in dry conditions but rushing waters clogged the narrow passages with mud and debris, blocking visibility and access.

How were they found?

They were finally reached by two British rescue divers late on Monday, nine days after they entered the caves.

They were huddled on a rock shelf about 4km (2.5 miles) from the mouth of the cave.

Media playback is unsupported on your device Media caption The moment divers discover the missing boys

The video of that first contact was also posted on Facebook by Thai navy special forces.

The boys are seen by torchlight sitting on a ledge above water, responding to the divers that all 13 are there and they are very hungry.

Media playback is unsupported on your device Media caption Diver Ben Reymenants is assisting with the rescue mission and says none of the boys can swim