US military joins search for boys' soccer team missing in Thailand cave Rising waters have hampered rescue efforts.

London -- Rising floodwaters are hampering search efforts to find a group of 12 teenage boys and their 25-year-old soccer coach trapped inside a cave in northern Thailand.

Around 30 members of the United States Pacific Command (USPACOM) as well as several British divers arrived in Thailand Wednesday to join the rescue attempts, now in their fifth day.

Thai soldiers prepared Thursday to drill a shaft in order for rescuers to gain better access to pockets of the cave where the group may be taking refuge.

Experts say Tham Luang, Thailand’s longest cave, has several chambers that could still be above floodwater levels.

Major Buncha Duriyapan, commander of the 37th Military District in Chiang Rai, said workers would drill from the top of the cave complex in order to open up a new tunnel entrance for rescuers.

“We will drill down from one of the chimneys…the expert divers went straight from the plane into the cave to make an assessment,” he told reporters.

The assessment was carried out by British specialists. Previous attempts to pump out water proved fruitless as relentless rains meant water levels were rising faster than teams could pump the water out.

An elite Thai SEAL team is also on site helping with 24-hour rescue efforts.

The boys, who are between 11-16 years old, went missing with their coach after he took them to the cave complex after soccer practice on June 24.

Interior Minister Anupong Paojinda told BBC journalists that officials were confident the children were “still alive.”

“They have food, they are skillful, we are confident they are safe,” he said.