Rescuers bid to free trapped explorer in Italian cave

A major rescue operation is underway northeast of the Italian city of Bergamo to free a woman considered an expert spelunker who was trapped while exploring a cave with eight others.

Ottavia Piana is blocked in a deep inside the Bueno Fonteno cave, where the temperatures were around 7C in high humidity.

Piana was injured after falling some five metres on Saturday evening during an expedition to map 1km of an uncharted branch of the cave, but rescuers said she is alert and responsive.

Rescuers reached her late on Sunday and have used small explosives in an attempt to breach the last 100m to get to her.

A spokesman for rescue operation, Mauro Guiducci, said it was impossible to foresee how long it would take to free Piana.

"One thing is certain, these kinds of operations are very long,'' Guiducci said.

He added that a team of 20 technicians were operating inside the cave and dozens more were assisting above ground.