The search and rescue mission to find a two-year-old boy who fell into a narrow, deep borehole in southern Spain more than a week ago has hit a major setback.

As the rescue team was preparing to lower miners into a new vertical shaft that runs parallel to the borehole the toddler fell into, they noticed that the rescue tunnel’s casing cannot be fed more than 131 feet because it is not wide enough.

Expert technicians said they are forced to widen the shaft’s diameter. An estimate on when this new task will be completed, El Pais reported.

"There were technical problems involved in putting tubes in the shaft beyond a depth of 131," said a government spokesman in Malaga, explaining that drilling work was under way to expand the hole.

SPANISH RESCUERS RUSH TO SAVE BOY, 2, WHO FELL DOWN WELL

The search-and-rescue team had hoped to start digging a horizontal tunnel at the bottom of the newly created shaft toward the boy’s presumed location.

There has been no contact with the boy – Julen Rosello – since he fell down the narrow borehole in the southern town of Totalan near Malaga on January 13 while playing as his parents prepared a picnic. The only sign of the toddler search-and-rescue teams have found so far is hair that matched his DNA inside the hole.

The rescue has been fraught with complications.

The borehole – or well – is blocked by a layer of earth, sand and stones believed to have been dislodged when the toddler fell. At just 10 inches wide, the borehole is too narrow for adults to enter.

An initial plan to reach him with an angled tunnel was abandoned after repeated collapses and landslides. Also, on Monday, digging of the shaft was temporarily halted to perform maintenance on the drill used.

The use of explosives was ruled out because they pose a danger to both the miners and the boy.

CLICK HERE TO GET THE FOX NEWS APP

Angel Garcia, the leading engineer coordinating the search-and-rescue, told reporters that they have across “very difficult material” that has made the process more difficult.

Once the diameter of the new shaft is widen, a specialized group of miners will be lowered in a specially-made cage to dig the horizontal tunnel. That laborious task is expected to take upwards of 24 hours, officials said.

"Those who are here risking their lives have faith that he is alive and that we will pull him out alive," Bernardo Molto, spokesman for the Civil Guard police force in Malaga province, told AFP. "If not, they wouldn't be working in these conditions."

According to reports, the borehole was unmarked at the time of the accident and regional authorities said they necessary permissions had not been sought before it was dug.

On Tuesday, Spain’s Civil Guard said it launched an investigation into whether the borehole was drilled illegally.

The Civil Guard's press office did not elaborate on the investigation.

People across Spain have been gripped by the plight of the boy and his family. The rescue attempt has suffered agonizing delays because of the rocky terrain.

The Associated Press contributed to this report.