Moroccan rescuers worked through the night into Saturday, the fifth day of an increasingly urgent and nerve-wracking effort to rescue Rayan, a five-year-old boy trapped underground in a well.

The complex, slow and risky earth-moving operation has gripped residents of the North African kingdom and even sparked sympathy in neighboring Algeria, a regional rival.

Rayan accidentally fell about 32 meters (35 yards) down the tight, empty shaft near his home in the remote village of Ighrane in Chefchaouen province on Tuesday afternoon.

Rescue crews, using bulldozers and front-end loaders, have dug almost all the way down but the final two meters are the most difficult because of the risk of landslides.

There has been no information about the fate of the boy, but the more time that passes, the more fears arise over whether he will be recovered alive.

Overnight, crews manoeuvred a heavy pipe into position in the area.

"We're almost there," said one of the operation's leaders, Abdesalam Makoudi, adding "tiredness is kicking in, but the whole rescue team is hanging on."

- Working through darkness -

A glacial cold has gripped this mountainous and impoverished region of Rif, which is at an elevation of about 700 metres.

On Thursday Moroccan media reported that rescuers managed to deliver oxygen and water to the bottom of the well.

Thousands of people gathered around the site, surrounded by olive trees, where AFP reporters said the tension was palpable. Some applauded to encourage the rescuers.

The shaft, just 45 centimetres (18 inches) across, was too narrow to reach Rayan, and widening it was deemed too risky -- so earth-movers dug a wide slope into the hill to reach him from the side.

The operation has made the landscape resemble a construction site. It involves engineers and topographers, and was made more complex by the mix of rocky and sandy soils.

Red-helmeted Civil Defence personnel have at times been suspended by rope, as if on a cliff face.

Working non-stop through the darkness, under powerful floodlights that gave a gloomy air to the scene, they are also digging a horizontal tunnel to reach the pocket where Rayan is, local authorities say.

- 'Moving a mountain' -

"I keep up hope that my child will get out of the well alive," Rayan's father told public television 2M on Friday evening. "I thank everyone involved and those supporting us in Morocco and elsewhere."

The boy's mother told Moroccan media that Rayan had been playing nearby when he disappeared on Tuesday afternoon.

"The whole family went out to look for him then we realised that he'd fallen down the well," she said with tears in her eyes.

The drama has sparked an outpouring of sympathy online, with the Arabic hashtag #SaveRayan trending across North Africa.

"Rescuers are literally in the process of moving a mountain to save little #Rayan. I hope that their efforts will not be in vain and that those who prayed for him will see their prayers answered," one internet user wrote.

The boy's fate has attracted crowds of people to the site, where parked cars lined the roads around the village and supporters are camping.

Police reinforcements have been sent, and the swarm of onlookers has sometimes impeded the rescuers' efforts.

Authorities have called on the public to "let the rescuers do their job and save this child."

But one volunteer said he was there to help. "We've been here for three days. Rayan is a child of our region. We won't leave until he's out of the well," he said.

The accident echoes a tragedy in Spain in early 2019 when a two-year-old child died after falling into an abandoned well 25 centimetres wide and more than 70 metres deep.

Julen Rosello's body was recovered after a search and rescue operation that lasted 13 days.