The perilous mission to evacuate 12 boys and their 25-year-old coach trapped deep inside a flooded cave in northern Thailand is under way, Thai authorities announced Sunday.

“Our readiness is at the highest today. Today is D-day,” said Chiang Rai’s governor, Narongsak Osotthanakorn, adding that the families had been informed of the plan and given their support to the rescue effort.

At 10 a.m. local time, an international contingent of 13 specialist divers descended into the watery network of underground tunnels below the Mae Sai mountains, carrying with them the hopes of an entire nation.

The plight of the stricken boys, who have remained trapped inside the caves for 15 days, has transfixed Thailand, as rescue efforts have become ever more urgent.

Rescuers have what has been described as a dwindling window of opportunity, with forecasters predicting the return of heavy monsoon rains in the coming days, effectively sealing off the cave until October.

•Sourced from CNN but headline original to News Express.