Rescuers in southern Spain say that the frantic effort to reach a two-year-old boy who fell into a narrow, deep borehole seven days ago has again been slowed by difficult terrain.

Provincial authorities said on Sunday that a drill used to create a vertical shaft parallel to the waterhole has hit a rocky patch.

There has been no contact made with Julen Rosello, who fell into the 360 feet shaft on Sunday in the countryside northeast of Malaga.

Experts are hoping to reach the boy by digging a horizontal tunnel to the spot where they believe he is trapped.

Rescuers hope to find him at a depth of 236 feet, where a soil blockage has hampered efforts to save him.

At just 10 inches wide, the borehole is too narrow for adults to enter.

The only sign of the boy that search-and-rescue teams have found so far is hair that matched his DNA inside the hole.

A specially-made cage has arrived at the site, ready to lower mining rescue experts down the shaft.

The experts then hope to dig a horizontal tunnel to the spot where they believe the boy is trapped in the borehole.

Angel Garcia, the leading engineer co-ordinating the search-and-rescue operation, said on Saturday that the horizontal tunnel would take at least another 20 hours to excavate.

People across Spain have been gripped by the plight of the boy and his family, as the rescue attempt has suffered agonising delays due to the rocky terrain.