A British spelunker has joined the rescue operation at a Thai cave, five days after a team of teenage soccer players and their coach went missing.

US forces also joined the search operation, at the Tham Luang-Khun Nam Nang Non cave in the Chiang Rai province.

The group of 12 teenage boys and their soccer coach went missing on June 23. Efforts to trace their whereabouts were hampered by heavy rainfall and floodwaters.

This video shows Vernon Unsworth, a cave explorer who lives in Chiang Rai, reports said, explaining the challenging nature of the rescue operation, and describing the layout of the cave network in which the team went missing.

Unsworth describes a junction, and says, “we are assuming they’ve gone left, but they could easily have gone right.”

He says if they went right, they would have faced 750 meters of crawling. Credit: Royal Thai Police via Storyful