MADRID (AP) — More than 100 firefighters and emergency workers in southern Spain searched Monday for a 2-year-old toddler who fell into a narrow and deep borehole.

Rescuers have been unable to get into the borehole, which is no wider than 25 centimeters (10 inches) in diameter and is believed to go down more than 100 meters (330 feet). On Monday afternoon they were deploying three different approaches to reach the bottom of the well but without damaging its structure or blocking it with soil and rocks, local authorities said.

According to rescuers, the boy fell into the hole early Sunday afternoon after walking away from his parents while playing in a mountainous area near the town of Totalan, northeast of the city of Malaga.

The hole, which is too narrow for an adult to enter, had been bored a month earlier during water prospection works and had not been covered or protected, local media reported.

The provincial representative of the Spanish government, Maria Gamez, said that firefighters using a robot camera in the early hours of Monday found a bag of candy that the boy was carrying when he went missing. It was some 75 meters down the shaft, where rescuers were unable to get their equipment further down.

Civil Guard spokesman Bernardo Molto told Spanish public broadcaster TVE that efforts would now focus on using more sophisticated equipment to widen the hole while also digging separate tunnels to access the shaft.

Asked whether the investigation is also considering any other reasons for the boy's disappearance, Molto told reporters that the authorities' priorities are "searching, locating and rescuing the boy."