The sudden flooding of a cave in Thailand's southern province of Surat Thani killed at least five German tourists and their two Thai guides and left two people missing, officials said on Sunday.
Heavy rains inundated Nam Talu Cave in Koh Sok National Park of Surat Thani, about 300 km south of Bangkok, while seven German tourists were visiting the popular site with two Thai tour guides Saturday, said park deputy chief Thirayudh Munagpaisan.
Rescue workers located seven bodies in the cave, including five Germans and the two guides.
"We are still optimistic that the two missing tourists are still alive since we probably would have discovered their bodies by now had they drowned," said Thirayudh.
He said the group had a taken a boat to the cave, about 60 km from the park headquarters, and were caught inside during a three-hour rainstorm that inundated the cavern.
Thirayudh claimed that park officials had issued warnings to tourists about the dangers of visiting the cave during the rainy season.
The names of the victims were not immediately available. They had been staying on floating bungalows on the Koh Sok reservoir.