CHIANG RAI, Thailand (Reuters) - A soccer team of 12 Thai schoolboys and their coach trapped in a flooded cave for the past fortnight established contact with their parents for the first time through heartfelt letters as rescuers strove on Saturday to find a way to save them.

Short notes scribbled by each schoolboy on smudged, yellowish paper showed both humor and homesickness as they sought to reassure their relatives they were in good spirits.

“Please don’t worry,” the boys said in a collective message before each wrote short personal messages to their loved ones.

“We’re all healthy and strong. There’s so much food we want to eat when we get out. We want to go straight home,” they wrote.

However, the fate of the boys trapped in the Tham Luang cave complex in northern Chiang Rai province remained unclear.

Narongsak Osottanakorn, Chiang Rai’s former governor, told reporters their best chance yet to free the party could be in coming days before heavy rains set in, although he did not give a precise timeframe for a rescue attempt.

Getting to the spot where the boys sought refuge takes a nearly 11-hour round trip through 4 km (2.5 km) of winding, and occasionally narrow, submerged pathways.

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Risks include further monsoon rains inundating the cave network and oxygen running out.

A former Thai navy SEAL diver, Samarn Kunan, died from a lack of oxygen on Friday as he navigated the cave complex close to the Myanmar border.

The boys, however, were already looking ahead and appealed to their schools not to be too hard on them.

“Teachers, please don’t give too much homework,” they wrote.

The correspondence was posted on a Thai Navy SEALs Facebook page early on Saturday that said the letters were brought out on Friday night.

It has not yet been possible to patch phone calls through the limestone hillside.

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The boys’ parents wrote their own notes, telling them they were greatly missed and urging them to take care and remain strong.

“We are waiting to throw you a birthday party,” wrote the parents of Pheeraphat Sompiengjai, the team’s right winger who is nicknamed “Night”.

Their son turned 16 on the day the boys first entered the cave, reportedly to have a picnic. They also emphasized that the coach shouldn’t blame himself for the incident and that they were grateful he had taken care of the children.

The parents couldn’t be reached for comment by Reuters.

Given the complexities of rescuing the boys, some of whom can’t swim, other options include laying an oxygen line to keep them alive during Thailand’s monsoon season, which could last for months, or drilling a shaft down into the cavern.

“Please don’t worry, Dad and Mum, I’m only gone for two weeks. I’ll help Mum with the shop every day I can. I’ll be there soon,” wrote Ekarat Wongsukchan, or Bill, the 14-year-old goalkeeper of the Wild Boars Academy team.

The boys’ plight has coincided with soccer’s World Cup, the sport’s major event that is being played in Russia.

Football’s world governing body, FIFA, has offered to fly the Thai boys and their coach to the World Cup Final in Moscow on July 15 if they are rescued before then.