Twelve boys and their assistant football team coach have been found alive by rescuers inside a Thai cave complex nine days after they went missing, an official said on Monday.

The boys, aged between 11 and 16, went missing with the 25-year-old coach after their practice on June 23.

It was after this they set out to explore the Tham Luang cave complex in Chiang Rai.

A massive international rescue effort has been underway since, with rescue teams battling through thick mud and high water to try to reach the group.

“Thai Navy seals have found all 13 with signs of life,” Chiang Rai province’s Governor Narongsak Osottanakorn told reporters.

Rescuers had been working on Monday to clear a constricted passageway for divers deep inside the flooded cave complex in a search operation that has been hampered by heavy rain.

Divers from Thailand’s elite Navy SEAL unit had been focusing on an elevated mound inside the cave which cavers have named “Pattaya Beach”.

The mound is believed to be a point which could have provided the boys with a refuge when rains flooded the cave.

“The SEALs reported that … they reached Pattaya Beach which was flooded. So, they went 400 metres further where we found the 13 … who were safe,” Narongsak told the cheering group of reporters.

The next challenge will be getting the group out of the cave, which some have dubbed a “labyrinth”.

Rescuers had discussed waiting until water levels subsided to get the boys out.

Other options included teaching the group to use diving gear to navigate the flooded cave.

Medical teams were seen preparing first aid kits after news of the group’s discovery broke outside the cave’s entrance.

Relatives of the boys took shelter from heavy rain on Monday and were seen cheering, smiling and receiving calls after receiving the news.

Rescuers shook hands and congratulated each other as occasional cheers broke out.

It remains unclear whether any of the group are injured or in need of medical attention.

Narongsak said medical teams have been sent inside the cave.

He added it would take them around four hours to assess the group’s health and how fit they are before coming up with a strategy to get them out. (Reuters/NAN)

•Rescue teams gather in a deep cave where a group of boys went missing in Chang Rai, northern Thailand, Monday, June 25, 2018.

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