Rescuers in Italy working to free cave explorer trapped underground

A major rescue operation was underway Monday 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 ranging from 7 degrees Celsius to 8 degrees Celsius (44-46 degrees Fahrenheit) in high humidity.

Piana was injured after falling some 5 meters (16 feet) Saturday evening during an expedition to map a kilometer (half a mile) of an uncharted branch of the cave, but rescuers said she is alert and responsive.

Rescuers reached her late Sunday and have used small explosives in an attempt to breach the last 100 meters (yards) 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, adding that a team of 20 technicians were operating inside the cave and dozens more were assisting above ground.