The terrifying moment a young boy was spotted inside the rhino enclosure at Dublin Zoo has been captured by social media users.

Several images show the boy in the company of an adult male – who significantly is standing outside the fence. And with the same images being shared on Twitter, many observers understandably expressed their concern.

One user who was at the zoo on Saturday said she saw the boy in the enclosure for a 'good 20 minutes'.

Asking SHEmazing not be named but confirming the incident with us, she had previously told the Irish Daily Mail: "The child didn’t look scared and nobody really passed any heed on what he was doing.

"The child stood there for a good while and the man kept letting go of his hand and telling him to move further back to pose for a picture."

Rathmines-based architect Ciarán Ferrie also spotted the ordeal, sharing two photos via his Twitter account. 

A spokesperson for the zoo said over the weekend that the "matter is being taken care of internally".

Dublin Zoo keeps several white rhinos as part of its African Plains attraction.

When the Plains initially opened in 2001, the animals – including zebra, ostriches, and giraffe – mingled together. However, after a female rhino charged at and killed a zebra in 2009, the rhinos were segregated into their own space.

At the time, a zoo official stated that the incident was an accident, but added that "there are no guarantees when you're dealing with wild animals".

Three years ago also at Dublin, a two-year-old girl was mauled by a tapir during a supervised visit to the animal’s enclosure. She was left with deep cuts on her arm and stomach and underwent surgery in Temple Street Children’s Hospital.

A decade ago, a 16-year-old girl scaled a two-metre fence to reach the Siberian tiger enclosure. She subsequently received significant injuries to her limb.

A Cincinnati Zoo in June, a three-year-old boy fell into the gorilla enclosure – resulting in the shooting dead of the ape. The boy was unharmed.

In Morocco last month, an eight-year-old girl died after she was accidently struck by a rock thrown by an elephant at Rabat Zoo.