CHIANG RAI - The chief engineer involved in the rescue mission to free a group of young footballers trapped in a cave in Northern Thailand said he thinks a team may be able to drill down to where the youngsters are located and get them out that way, The Guardian reported.

Drilling was previously believed to be too dangerous an option, given the small space the boys, aged 11 to 16, and their 25-year-old coach are trapped in, and the fact that they are believed to be between 800m and 1km below the surface.

Thai authorities are progressing several different plans at once to try to reach the boys - including drilling a hole from the top of the mountain to find them.

Thanes Weerasin, the president of the Engineering Institute of Thailand, who is supervising a drilling crew currently in the jungle above the boys, told The Guardian he was exploring one particularly promising tunnel with a large hole about 100m into it.

"It's a big hole, about 1.2m by 1m," he said. "You can go down using a rope... I think this place can lead to the children because after your foot touches the ground below, you can walk through using the compass and direct it to the tunnel (where the children are stuck)."

About 20m in the direction of the boys, Weerasin said he reached another hole that was obstructed by a boulder. He wedged a borescope through a gap and saw it extended up to another 10m.

He believes the hole leads to the boys because when he lit a fire, smoke flowed quickly through cracks around the boulder, presumably because of the water being pumped from the main cave on the other side.

"It went very quickly. I think that is caused by the pumping of the water from the end of the tunnel and outside at the entrance," he said.

He believes the hole could eventually lead to Nom Sao slope, the area past Pattaya Beach where the children and their coach are sheltering. "I think this hole is near there."